Preheat the oven to 350°F.
Combine both sugars, salt, flour, and oatmeal in a bowl, and cut in butter to make a crumbly crust.
6 Tablespoons salted butter, ½ cup granulated sugar, ¼ cup brown sugar, ¼ teaspoon salt, ⅔ cup all-purpose flour, ½ cup old-fashioned oatmeal
Press ⅔ of the crust mixture into an 8x8-inch baking pan.
Bake in the center of the oven for 10 minutes.
While the crust is baking, blend cream cheese, granulated sugar, vanilla, sour cream, eggs, and lemon juice together until smooth. Stir in blueberries.
1 (8-ounce) package cream cheese, ⅔ cup granulated sugar, 1 teaspoon vanilla extract, ⅓ cup sour cream, 2 large eggs, 1 Tablespoon lemon juice, 1 cup blueberries
Pour over the crust, and sprinkle the reserved crust over the top.
Bake for an additional 25 minutes, until the cheesecake bar slab is set around the edges but still slightly jiggly in the center.
Remove from oven and let cool completely in pan before cutting into squares.