Step 1

Preheat the oven to 350°F. Generously grease an 8-inch baking pan and line with parchment paper.

Step 2

Chop the chocolate into smaller pieces and melt the chocolate in a microwave-safe bowl for approximately 2 minutes at 50% power. Stir every 30 seconds until completely melted and smooth. Set aside to cool.

Step 3

Melt the butter in a microwave-safe bowl and combine with the granulated sugar; beat together until well combined.

Step 4

Next add the egg and egg yolk and beat for 60-90 seconds at a higher speed until the batter is fluffy (texture resembling a cake batter). Then add the vanilla extract and melted chocolate and beat until combined.

Step 5

Combine the dry ingredients in a separate bowl and stir to combine. Add the dry ingredients to the batter and mix just until combined. Fold in the chocolate chips with a spatula. Set aside.

Step 6

In a mixing bowl, beat the cream cheese and sugar until well combined and free of any lumps, scraping down the bowl as needed.

Step 7

Next beat in the eggs and vanilla extract until well combined and completely smooth. Set aside.

Step 8

Spread the 2/3 of the brownie batter in the prepared pan. Then spoon 2/3 of the cheesecake batter over the brownies. Finally, spoon the remaining brownie batter and cheesecake batter and swirl with a knife.

Step 9

Bake at 350°F for 35-40 minutes. Toothpick should still be somewhat gooey but not wet in the center. Remove from the oven and allow to cool prior to cutting. Store in an airtight container.