01 -
Preheat the oven to 175°C (350°F).
02 -
In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy. Incorporate the eggs, vanilla extract, and 135 grams of creamy peanut butter, mixing thoroughly.
03 -
In a separate bowl, combine baking soda, salt, all-purpose flour, and rolled oats.
04 -
Gradually add the dry ingredients to the wet mixture, stirring until fully integrated. Press the batter evenly into a well-greased 9x13 inch (approximately 23x33 cm) baking pan.
05 -
Bake in the preheated oven for 17 to 21 minutes, or until the surface is no longer glossy and the center is just set. Avoid over-baking to prevent hardening. Allow to cool completely in the pan.
06 -
Once cooled, spread a thin, even layer of creamy peanut butter over the surface of the bars.
07 -
Melt butter in a small skillet over medium heat. Stir in cocoa powder until smooth. Remove from heat and whisk in milk, powdered sugar, and vanilla extract until the frosting is smooth and lump-free. Use electric beaters if necessary.
08 -
Spread the prepared chocolate frosting evenly over the peanut butter layer. Allow the frosting to set before slicing and serving.