12ouncessemi-sweet OR dark chocolate, finely chopped
1cup(8 ounces) unsalted butter, melted until browned
1cuplight brown sugar, packed
5large eggs, at room
1cuppeanut butter chips
15full-size peanut butter cupsplus more for decorating, optional
Preheat the oven to 350 degrees (F). Line a 9×13 inch baking pan with parchment paper; spray paper and any exposed pan with non-stick baking spray and set aside.
In a medium bowl, combine the flour, cocoa powder, and salt; whisk well and set aside. Place chopped chocolate in a large bowl and set aside. Melt butter in a medium-sized skillet over medium heat. Continue cooking butter, stirring frequently, until it's a light amber color and smells slightly nutty. Remove from heat at once and pour over the chopped chocolate. Let the chocolate/butter mixture sit for 2 minutes, then whisk smooth. Add both sugars and vanilla and whisk smooth. Add 3 of eggs to the chocolate mixture and whisk until combined. Add the remaining eggs and whisk until combined. Do not overbeat the batter at this stage or your brownies will be cakey. Sprinkle the flour/cocoa powder mixture over the chocolate mixture. Using a rubber spatula (not a whisk), fold the flour mixture into the chocolate until just a bit of the flour mixture is visible. Fold in the peanut butter chips. Don't worry if they melt into the batter! Pour the batter into the prepared pan and smooth the top. Press the peanut butter cups into the batter, making 5 rows with 3 peanut butter cups in each row. Use a spatula to cover each peanut butter cup with brownie batter. You don't want any of the peanut butter cups showing.
Bake in the center of the oven for 32 to 35 minutes, rotating the pan halfway through the baking time, or until a toothpick inserted into the center of the brownies comes out with a few moist crumbs sticking to it. Press peanut butter cups on top of warm brownies, if desired.
Let the brownies cool completely in the pan (this will take about an hour to an hour and a half), then lift them out of the pan using the parchment paper. Cut into squares and serve. *To speed up the cooling process, you can pop the tray in the fridge.
Store at room temperature, in an airtight container or wrapped tightly with plastic wrap, for up to 3 days.
Total time does not include cooling, which will take at least an hour. For tips and tricks on recipe success, please see post!