Preheat oven to 350 degrees F. Line a 9-by-13-inch square baking pan with parchment paper or lightly spray with nonstick spray.

In a small bowl, whisk together flour, cocoa powder, baking soda, baking powder, and salt. Set aside.

In a large, microwave safe bowl, heat butter pieces and chopped chocolate in the microwave for about 45-60 seconds, stirring every 15 seconds or so, until chocolate is mostly melted. Stir until smooth and chocolate is fully melted. Set aside and let cool for 5 minutes, then mix in granulated sugar.

Add eggs, egg yolk, and vanilla extract and whisk until smooth.

Fold in dry ingredients until almost incorporated, then add chocolate chips and fold until evenly distributed and no dry ingredients remain.

Spread evenly into prepared pan.

Bake for 25 to 30 minutes or until set and puffed in the middle.

Remove from oven and let cool to room temperature.

For the topping, place chocolate in heat-proof bowl. Heat cream in a small saucepan until it just starts to simmer around the edges.

Pour over chopped chocolate and let set for 30 seconds, then stir until melted and smooth.

Pour over top of cooled brownies, reserving ¼ cup of ganache if desired for a drizzle at the end.

While glaze is still wet, sprinkle evenly with peanut butter cups, kettle corn, and potato chips, pressing lightly so they stick into the ganache.

Cover and refrigerate until set, at least 2 hours or overnight.