You have the lunch lady to thank for these old school cafeteria-style Peanut Butter Cookie Bars that have a chewy peanut butter oatmeal cookie base and a thin layer of salty-sweet melted peanut butter underneath those rich swirls of chocolate frosting.
If you want more easy peanut butter desserts, be sure to also check out our Copycat Levain Bakery Dark Chocolate Peanut Butter Chip Cookies, Peanut Butter Swirl Brownies, and No-Bake Peanut Butter Pie!
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These peanut butter oatmeal bars with chocolate frosting are dangerous to have around. I can't make them for just my family of four unless we are having friends over or we are taking them someplace because I legit cannot resist the temptation. They are great for a crowd and things like potlucks, picnics, and bake sales.
I was recently reminded of these peanut butter cookie bars when we went to a place in Utah called Blox Dessert Bars. One of their signature dessert bars is called "The Skippy" which is a peanut butter blondie with chewy oats that is topped with a layer of melted peanut butter and rich chocolate frosting.
You might know or remember them as "lunch lady peanut butter bars" if you grew up in a certain era. I grew up back when school cafeteria lunch was still pretty decent. Sloppy joe day was always my personal favorite.
But what I really remember are the treats that the lunch ladies would make. I practically subsisted on the chewiest, thickest rice krispies treats with super stretchy marshmallows through high school. And their hardly baked, giant chocolate chip cookies were basically just molten dough that was literally scalding and so gooey that they were essentially raw. You could buy them at the cafeteria in the morning before school started, which was pretty much how I began every day.
These days dessert isn't offered as part of a "healthy" school lunch, and most schools are "nut-free" anyway. But these classic peanut butter bars will forever immortalize the stalwart lunch ladies in my memory.
Why this Recipe Works
- No need to scoop and frost individual cookies. Like sugar cookie bars, you just bake up one big pan and then slice them into squares. Done.
- The dough is slightly softer and more spreadable than regular cookie dough so it can be pushed into the corners of a large baking sheet.
- There is a thin layer of straight peanut butter between the cookie base and the creamy chocolate frosting on top. Don't skip it. It adds a density and intensity to these bars that is out-of-this-world.
Ingredient Notes
- Peanut Butter: I used creamy peanut butter, but crunchy will work just as well.
- Oatmeal: I like using old-fashioned oats best because they give a chewier texture, but quick oats will work as well.
- Cocoa powder: I just used Hershey's unsweetened natural cocoa powder for the frosting in this recipe because it's always readily available.
- Sugar: A combination of granulated sugar and brown sugar gives depth and just the right amount of sweetness to the base of these yummy bars.
How to Make This Recipe
Start out by creaming the butter, granulated sugar, brown sugar, and peanut butter together in a large bowl until smooth. Then add the eggs and vanilla extract and beat again, scraping the bottom and sides of the bowl so everything mixes together evenly.
Add the dry ingredients to the creamy mixture, then mix again just until combined. Stop and scrape the bottom and sides of the bowl again to make sure that the oats especially are nice and evenly dispersed throughout the oatmeal peanut butter cookie dough.
Spread or press the cookie dough into a half baking sheet that has been sprayed with baking spray. These are the normal sized 13"x18" rimmed baking sheets that we use all the time for making cookies.
The dough is thick, but you should be able to press it into the corners of the pan using a spatula. It doesn't need to be perfect since the soft dough will spread and puff a bit as it bakes anyway. Bake for about 15 minutes until the edges are barely turning golden brown and the bars are set, but don't overbake.
While the bars are still hot, heat some additional peanut butter in the microwave for 45-60 seconds until it's melted, then drizzle it over the top and spread it in a thin, even layer.
You could just plop on some spoonfuls of the peanut butter without bothering to melt it in the microwave and the residual heat of the bars will do most of the work for you, but sometimes it doesn't quite melt all the way and when I go to spread it the warm, soft cookie part underneath lifts up, so I think it's worth it to melt the peanut butter first.
Let the bars cool COMPLETELY at this point. It's painful to wait, I know, but if you top them with the chocolate frosting while the bars are still warm, the frosting will melt. Once the bars are cool, the peanut butter will solidify back into a firm layer and you can easily spread the chocolate frosting on top of the bars.
Slice them into large squares (this recipe makes 2 dozen large squares) or smaller rectangles, then serve.
Recipe FAQ's
If you have a peanut butter allergy, these could definitely be made with cookie butter instead and I'm sure they would be delicious, just like my Biscoff Cookie Butter White Chocolate Chip Cookies. I'm also pretty sure almond butter or sunflower seed butter would also work just as well.
You can use a 1-to-1 gluten-free baking flour replacement for the flour in this recipe. Just be careful with your oats since some oats actually do have gluten in them.
Recipe Tips
- Storage: Keep your bars covered in an airtight container on the counter for 5-7 days. Some rimmed baking sheets come with a plastic lid that is perfect for just this sort of occasion. Or you can just cover them with plastic wrap once the frosting has dried and firmed up a bit. You can also keep the bars in the fridge and serve them chilled, if you prefer.
- Freezing: These freeze great for 2-3 months. For easier storage, I recommend slicing and separating the bars, then freezing them individually for an hour to set the frosting. Then you can transfer them to a freezer-safe container and stack them so they don't take up as much space in the freezer.
- Variation: If you STILL can't get enough peanut butter chocolate action, try chopping up some Reese's peanut butter cups to sprinkle on top. Or sprinkle with some Reese's Pieces or chopped dry roasted peanuts instead.
More Dessert Bar Recipes
- Carmelitas (Oatmeal, Chocolate, Caramel Bars)
- Oatmeal Fudge Bars
- Pecan Pie Cheesecake Bars
- Classic 7 Layer Bars
Brownies and bars
Classic Nanaimo Bars
Brownies and bars
Smores Bars Recipe
Brownies and bars
Strawberry Rhubarb Crumb Bars
Did you make this recipe?
Let me know what you thought with a comment and rating below. You can also take a picture and tag me on Instagram @houseofnasheats or share it on the Pinterest pin so I can see.
Lunch Lady Peanut Butter Bars
Ingredients
Bars
- 1 cup salted butter, softened (227g)
- 1 cup granulated sugar (200g)
- 1 cup packed light brown sugar (200g)
- 2 ½ cups creamy peanut butter, divided
- 2 large eggs
- 2 teaspoons vanilla extract
- 2 cups all-purpose flour, scooped & leveled (282g)
- 2 cups old-fashioned oats
- 1 teaspoon baking soda
- 1 teaspoon salt
Frosting
- ½ cup salted butter, softened (114g)
- 3 cups powdered sugar
- 4 Tablespoons cocoa powder
- ¼ cup milk
- 2 teaspoons vanilla extract
Instructions
- Preheat oven to 350°F. Spray a half-sheet baking sheet (13"x18") with baking spray.
- Beat the butter, granulated sugar, brown sugar, and 1 cup of the peanut butter in a mixer until creamy and light. Add eggs and vanilla extract, then beat again, scraping the bottom and sides of the bowl.
- Add the flour, oats, baking soda, and salt. Mix just until combined. Spread the peanut butter oatmeal cookie dough into the prepared pan with a spatula. Bake for 15-17 minutes until golden brown around the edges and barely set in the middle. Do not overbake.
- While the peanut butter oatmeal cookie base is still hot, melt the remaining 1 ½ cups of peanut butter in the microwave in a microwave safe bowl for 1 minute, then drizzle over the top of the bars, spreading it into an even layer with a spatula or knife. Let cool completely until the peanut butter has firmed up. This can be sped up by sticking the bars in the fridge.
- Make the chocolate frosting by beating the butter, powdered sugar, cocoa powder, milk, and vanilla extract in a large bowl until smooth. Spread in an even layer over the cooled bars, then cut into squares.
Video
Notes
- Storage: Keep your bars covered in an airtight container on the counter for 5-7 days. Some rimmed baking sheets come with a plastic lid that is perfect for just this sort of occasion. Or you can just cover them with plastic wrap once the frosting has dried and firmed up a bit. You can also keep the bars in the fridge and serve them chilled, if you prefer.
- Freezing: These freeze great for 2-3 months. For easier storage, I recommend slicing and separating the bars, then freezing them individually for an hour to set the frosting. Then you can transfer them to a freezer-safe container and stack them so they don't take up as much space in the freezer.
- Variation: If you STILL can't get enough peanut butter chocolate action, try chopping up some Reese's peanut butter cups to sprinkle on top. Or sprinkle with some Reese's Pieces or chopped dry roasted peanuts instead.
- Gluten-free version: You can use a 1-to-1 gluten-free baking flour replacement for the flour in this recipe. Just be careful with your oats since some oats actually do have gluten in them.
- Allergy-friendly: If you have a peanut butter allergy, these can be made with cookie butter, almond butter, or sunflower seed butter instead.
If this doesn't take me back to childhood! These were always the best for school lunches! Excited to give these a try!
I remember these, but ours came sans the frosting. So good. Looking forward to trying this as well.
These are actually truly irresistible. I ate 3 before I made my husband take them away from me so I wouldn't eat the whole batch.
Glad to hear they were such a hit, Marie! 🙂
Just made these, and they're perfect! Such a good peanut butter flavor. New favorite. Thanks for sharing!
Yay! I'm glad they were a hit!
The absolute best thing ever!
MMMMM
Super yummy. I made these as soon as I found the recipe. I used canned fudge frosting instead making it because I had some on hand. Also, I only made 1/4 of the recipe. Full recipe would have been way too much.
These are very good!
Best lunch lady pb bars ever!! I make them for almost every event I go to because everyone raves about how amazing they are!
I have had these.. they are delicious 🙂
they look Good will make them soon,thanks
I made the bars WITHOUT the pb topping and frosting and they are INCREDIBLE. They are thin but dense and super moist and chewy. A keeper recipe fir sure. Thank you!
We use to make these bars only we called them “Magic cookie bars!
My family loves these bars,I made them for memorial day all gone same day, but I'd double it.
Thank you for sharing your recipes! I enjoy trying new recipes. I live on a farm and I'm always baking things for a lunch break for the guys working out on the farm! Will enjoy your recipes!
I'm glad you found my site! Let me know if there is anything you are looking for that you don't see!
Halve recipe for 13x9 pan.
Made this today, was really good thanks for sharing
These are awesome. So awesome, in fact, that I cannot make these too often or I'd better be taking these somewhere as a dish to pass!!! lol
Thanks for the recipe :))
Ha ha Oh I completely understand. If I make these I have to plan on giving some to friends or else I will eat them all! They're so good! Thanks for the review!
Thanks for your good 👍 Recipe,s
Thank you for letting me have your Recipes l like the old recipes the Best 😜
Delicious everytime! For cookie base, I used 1/2 cup of Biscoff cookie butter and 1/2 cup of peanut butter. Always a hit and perfect for large crowds.
Can I use self rising flour to make these with?
I don't see why not. I would just omit the baking soda and maybe decrease the salt to 1/2 teaspoon.
I assume I need to use whole milk? Not 2% or 1%?
Honestly it doesn't matter. You can use any type of milk. Whole milk will make it a tad creamier but it's such a minimal amount that you probably won't even notice the difference. I've made the frosting with with 2% and 1% and haven't noticed a huge difference.
This is the yummy treat I've had in a while. I added melted chocolate chips w/coconut oil drizzled over the top to add a little crunch and a finishing touch.
These bars are delicious!!! The kids loved them!
We love them too! I'm so glad you enjoyed them!
Perhaps I’m misreading, the weight for the butter by grams in the frosting portion is the same weight listed in the cookie base. Am I using a full cup of butter for the frosting?
No, sorry! That was a typo. I fixed it!
This is exactly the kind of desert I like, and this recipe was perfect. I live alone so I cut all the ingredients amounts down by 1/2 and made a 9x13 (quarter sheet). The cookie bake is exactly right, crunchy edges, chewy insides - the melted PB layer adds depth, like you said (I used chunky Skippy) and the chocolate layer is rich and sweet without being too sweet. It's five stars for me - chefs kiss. You did the lunch ladies proud.
p.s. I came here by way of FB, via BareFeetInTheKitchen
Aww, thank you, Lisa! I love that you made a half batch - I have this one on my list for a small batch version because we are a family of four and this makes a BIG pan and it's always sooooo tempting for me.
Very good recipe!! Easy to follow and tastes excellent. They were just a touch to sweet though. I would recommend adding a pinch of salt to the chocolate frosting, and I may even half the frosting recipe next time as well because I had quite a thick layer. But, will definitely make again!!
Thanks! Yes, adjust to how you like it!
I just finished making these and the people have just finished taste testing. Everyone is raving about them and asking when I'll be making them again. The answer is, soon, very very soon!!
The couple of things I did differently than the written recipe:
1. For the middle peanut butter layer I used half of what is called for (so, 3/4 of a cup) and it is just right, for us.
2. I felt like the 13 x 18 inch sheet would be stretching the batter very thin and so I used a 15 x 10 inch sheet and basically the same baking time applied (18 minutes), they cooked just fine. They really aren't very thick at all either, I'm glad I went with the slightly smaller cookie sheet.
These are fantastic, delicious, all the yummy words! Thanks so much for offering up this recipe, thrilled to have found it.
So good!!! Like a pb oatmeal cookie with chocolate icing. Perfect amount of sweetness and chew. Saved.