Hot Fudge Brownie Cheesecake

Preheat oven to 350°F (175°C). Grease a 9-inch springform pan.
Melt butter in a medium saucepan over low heat. Remove from heat and stir in sugar, eggs, and vanilla.
Beat in cocoa powder, flour, salt, and baking powder until well combined.
Spread the brownie batter into the prepared pan.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
For the Cheesecake Layer

In a large bowl, beat the cream cheese and sugar together until smooth and creamy.
Add eggs one at a time, beating well after each addition. Stir in vanilla.
Pour the cheesecake mixture over the hot brownie base.
Return to the oven and bake for 35-40 minutes, or until the cheesecake is set (it should jiggle slightly in the center).
Allow to cool completely, then refrigerate for at least 4 hours or overnight.
For the Hot Fudge Topping