01 -
Preheat the oven to 175°C (350°F).
02 -
Beat together the room temperature butter, granulated sugar, and light brown sugar until light and fluffy.
03 -
Incorporate the eggs, vanilla extract, and creamy peanut butter into the creamed mixture until smooth.
04 -
Mix baking soda, salt, all-purpose flour, and rolled oats in a separate bowl.
05 -
Fold the dry ingredients into the wet mixture and press the dough evenly into a greased 23x33 cm (9x13 inch) baking pan.
06 -
Bake for 17 to 21 minutes until the center is just set. Allow to cool completely before proceeding.
07 -
Spread a thin, even layer of creamy peanut butter over the cooled baked base.
08 -
Combine melted butter and cocoa powder in a saucepan over low heat. Remove from heat and stir in milk, powdered sugar, and vanilla extract until smooth.
09 -
Evenly spread the chocolate frosting over the peanut butter layer using a spatula.