Ingredients
For the Bars:
1 cup salted butter, softened
1 cup granulated sugar
1 cup packed light brown sugar
2 large eggs
2 ½ cups peanut butter
2 cups all-purpose flour
2 cups oats
1 teaspoon baking soda
1 teaspoon salt
1 teaspoon vanilla extract
For the Frosting:
½ cup salted butter, softened
3 cups powdered sugar
¼ cup cocoa powder
¼ cup milk
2 teaspoons vanilla extract
Instructions
Preheat & Prepare the Pan:
Preheat your oven to 350°F (175°C).
Lightly grease a half-sheet pan (13 x 18 inches) with baking spray.
Make the Dough:
In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until smooth.
Add the eggs and vanilla extract, then mix again until well combined.
Stir in the peanut butter until fully incorporated.
Gradually add the oats, flour, baking soda, and salt, mixing just until combined.
Bake the Bars:
Spread the dough evenly into the prepared baking pan, using a spatula to smooth the surface.
Bake for 15–17 minutes, or until the edges are golden brown. Be careful not to overbake.
Cool Completely:
Let the bars cool fully in the pan before frosting.
Prepare the Frosting:
In a separate bowl, beat together the softened butter, powdered sugar, cocoa powder, milk, and vanilla extract until smooth and creamy.
Frost & Serve:
Once cooled, spread the frosting evenly over the bars.
Cut into squares and enjoy!
Notes:
These bars are a nostalgic, school-lunch-inspired treat, perfect for sharing or as a snack.
For best results, let them cool completely before frosting to prevent a melted, glaze-like texture.
They store well for up to a week and freeze beautifully for longer storage.