Preheat the oven to 350 degrees F.

Heat a 10 to 11-inch oven-safe deep saute pan/skillet over medium heat. Add the butter. Once melted, turn off the heat and whisk in the sugars until dissolved. Whisk in the eggs, making sure to quickly combine them so they don’t cook. Whisk in the vanilla extract.

In a bowl, stir together the flour, cocoa, espresso powder and salt. Add it to the skillet and stir until combined and on lumps remain. Stir in the chocolate chips. Dollop the peanut butter all over the batter then swirl it in with a knife.

Bake the brownie skillet for 25 to 30 minutes, or until it is just barely set. You don’t want to overcook it! When it comes out of the oven, you can sprinkle with chocolate chips if you wish.

Let cool slightly then serve topped with vanilla ice cream.