Combine powdered sugar, peanut butter, butter, finely chopped peanuts, and vanilla in a large bowl. Mix well using a hand mixer or stand mixer. Add the milk, if needed, to get the mixture to come together. It might still be a bit on the crumbly side, but should hold together when pressed.

Scoop balls of dough using a small cookie scoop (about 2 tablespoons). Shape into egg-shaped balls, then flatten to about ½-inch thick on a baking sheet lined with parchment paper. Place in the freezer for 30 minutes.

When the peanut butter eggs are cold, melt the chocolate in the microwave in 20 second bursts of heat, stirring well between each burst until the chocolate is melted.

Use forks to dip each egg, turning to coat in the chocolate and then immediately transferring to a baking sheet lined with a clean sheet of parchment paper or waxed paper to set up. Repeat with remaining eggs.

Decorate with remaining melted chocolate by transferring it to a disposable piping bag or ziploc bag and snipping off the tip. Drizzle zigzags over the eggs or use it to personalize the eggs with names.