Grease a 9"x9" square baking pan, line it with parchment paper, and lightly oil the parchment. Preheat the oven to 325℉ and set a rack to the middle.
Place the cream cheese and allulose in a mixing bowl and beat with an electric mixer until the cream cheese is light and fluffy.
Add the egg and vanilla extract and continue to beat until there are no lumps and it is a smooth, creamy batter. This may take up to five minutes.
In a small bowl, mix the Keto Chow with the cocoa powder and baking powder and set aside.
Place the butter and chopped chocolate in a large, microwave safe mixing bowl and microwave in 10-second bursts, stirring after each burst, until the butter and chocolate are melted.
Stir the butter and chocolate together well and then stir in the allulose and brown erythritol.
Mix in the eggs one at a time, stirring well after each addition.
Stir in the dry ingredients and mix until the batter looks glossy and thick.
Spread the brownie batter out in the prepared pan as evenly as possible. It will be thick.
Spread the cheesecake batter over the brownie batter.
Bake for around 20-25 minutes, or until the edges are beginning to set, and the edges of the cheesecake layer are starting to look golden. The center will still be slightly jiggly.
Allow brownies to cool at least 30 minutes before cutting them into 16 pieces.