1. Preheat oven to 350°F (175°C). Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides.

2. Melt butter in a saucepan. Remove from heat and stir in sugar, eggs, and vanilla.

3. Add cocoa powder, flour, salt, and baking powder. Mix until smooth.

4. Spread brownie batter in the pan and bake for 20–22 minutes until set. Let it cool.

5. Lower oven temperature to 325°F (163°C).

6. In a large bowl, beat cream cheese until smooth. Add sugar and mix well.

7. Add vanilla, then eggs one at a time, beating on low. Scrape the bowl between each addition.

8. Blend in sour cream and heavy cream until batter is smooth and lump-free.

9. Wrap the pan in foil. Pour cheesecake batter over brownie layer.

10. Place pan in a roasting pan. Add hot water halfway up the sides for a water bath.

11. Bake for 60–70 minutes until center is slightly jiggly.

12. Turn off oven, crack door, and let cool inside for 1 hour.

13. Cool to room temp, then refrigerate at least 6 hours or overnight.

14. For fudge topping, melt chocolate chips, heavy cream, and butter over low heat until smooth. Let cool slightly.

15. Just before serving, top cheesecake with whipped cream, drizzle fudge, sprinkle nuts and brownie bits, and place a cherry on top.