Over low heat, melt 2 sticks of butter in a light-colored pan. Gently swirl the pan every minute until the butter turns a light golden brown. This takes 5 - 10 minutes total. Allow to cool for 5 minutes.
On medium speed, beat together the melted butter and sugars. Add in the peanut butter and mix well. Next, add the eggs and vanilla. Finally, add the flour, creating a small well for the baking soda, baking powder, and salt (this saves you a bowl! Holla!) Slowly mix in until well incorporated, then fold in the chocolate chips and peanut butter cups. In a small bowl, combine filling ingredients.
Place a sheet of parchment paper in a 13x9 inch baking dish. Spread half the cookie dough over the bottom in an even layer. Pour the filling over the top, then dot the top with the rest of the cookie dough.
Bake for 30 - 35 minutes until golden brown in color. Allow to cool for an hour before cutting.
What really sets these apart? The browned butter! Sure, you could just use melted butter, but why not step it up a notch? Browned butter adds a nutty, toffee flavor and rich color.