For the Brownies

1. Preheat your oven to 350 degrees Fahrenheit. Line a 9×13 baking dish with parchment paper.
2. In a large bowl, mix light brown sugar, granulated sugar, and room temperature eggs for two minutes with a whisk or electric mixer.
3. Add melted butter and vanilla extract to the batter and mix until combined.
4. Carefully, whisk all purpose flour, cocoa powder, and salt into the batter. Do not overmix, as doing so will lead to drier, cakier brownies. Scrape down the sides and bottom of the bowl to ensure all of the ingredients are properly incorporated. Batter will be thick.
5. Transfer batter to prepared pan, using a knife or spatula to spread the batter evenly across the pan.
6. Bake for 18-24 minutes or until a toothpick inserted into the center comes out with slightly moist batter. The toothpick should not come out clean but should not be wet. The top will look slightly wet and shiny.
7. Allow brownies to fully cool before proceeding.

For the Cheesecake 

1. In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with an electric mixer, beat softened cream cheese until smooth, about 2 minutes on medium speed.
2. Slowly, add powdered sugar to the cream cheese and beat on medium speed until smooth and velvety in texture. Add 1/8 teaspoon salt and vanilla extract to the mixture and beat until incorporated.
3. In a microwave safe bowl, heat peanut butter for 10-15 seconds. Stir the peanut butter before adding it to the cream cheese mixer. Beat on low speed and scrape down the sides and bottom of the bowl as needed to ensure the peanut butter fully incorporates.
4. In a separate, large bowl, beat heavy whipping cream and 2 tablespoons of powdered sugar on medium/high speed with an electric hand mixer or in a stand mixer with a whisk attachment. Beat until the mixture forms stiff peaks. This should take several minutes, but be patient. The mixture should look white, fluffy, and should look much greater in volume. When you remove the beater from the mixture, it should create a peak that sticks straight up and does not curl.
5. Carefully, fold the whipping cream mixture into the cream cheese mixture with a spatula. Continue folding until there are no longer streaks of white from the whipped cream.
6. Transfer the cheesecake mixture to the cooled pan of brownies. Use a knife or spatula to spread the cheesecake evenly across the pan of brownies.
7. Place the pan in the freezer while preparing the ganache to create a firmer surface to spread the ganache over.

For the Ganache + Decor

1. Place dark chocolate chips in a medium-sized bowl.
2. In a small saucepan, heat heavy cream until the mixture just starts to boil. It should be slightly beyond a simmer but should not fully bubble.
3. Immediately, pour the hot heavy cream over the chocolate chips. Use a knife or spoon to push the chocolate chips under the heavy cream, as the ganache may have some unmelted chunks of chocolate chips if you do not ensure they have all been touched by the hot cream. Let the mixture sit for about 3 minutes.
4. Using a whisk, start by making small circles in the center of the bowl. As you start to see the mixture coming together in the center of the bowl, slowly begin working outside the center, moving further towards the outside of the bowl as the ganache combines.
5. Pour the ganache over the cheesecake and spread using a knife or spatula.
6. Crush Reese’s cups over the top of the ganache for garnish.
7. Place the pan, covered with a piece of cling wrap to maintain freshness, in the fridge for at least 6 hours to allow the cheesecake to set.