Preheat your oven to 350°F (175°C). Grease and line the bottom of a 9-inch springform pan with parchment paper.

Melt the butter in a medium saucepan over low heat. Stir in the granulated sugar, and beat in the eggs, one at a time, followed by vanilla extract.

In a separate bowl, whisk together cocoa powder, flour, salt, and baking powder.

Gradually add the dry ingredients into the wet mixture until just combined.

Pour the brownie batter into the prepared pan and bake for 20-25 minutes, or until a toothpick inserted comes out mostly clean. Let cool.

Reduce the oven temperature to 325°F (163°C). In a large bowl, beat the softened cream cheese until smooth.

Gradually add the sugar, then mix in sour cream and heavy cream.

Beat in the eggs one at a time, and mix in the vanilla extract.

Pour the cheesecake batter over the cooled brownie layer.

Place the springform pan in a larger pan and fill it halfway with hot water to create a water bath.

Bake for 60-70 minutes, until edges are set but center is slightly jiggly. Let it cool in the oven.

In a saucepan, combine sugar, cocoa powder, and salt. Stir in butter and heat until melted, then add heavy cream gradually while stirring.

Cook until the sauce is combined and smooth, then add vanilla extract.

Once cooled, refrigerate for at least 4 hours before serving.

Spread hot fudge sauce over the cheesecake and top with whipped cream, cherries, crushed nuts, and chocolate shavings.

Slice and enjoy!