Step 1: Prepare Pan & Oven

Preheat oven to 325°F (165°C).

Line the bottom of a 9-inch springform pan with parchment paper and lightly grease the sides.

Step 2: Make the Brownie Base

Melt butter and allow to cool slightly.

Whisk in sugar, then eggs (one at a time), followed by vanilla.

Sift in cocoa powder, flour, salt, and baking powder. Mix just until combined.

Spread batter evenly into prepared pan.

Bake for 18–22 minutes, until just set but slightly underbaked. Set aside to cool.

Step 3: Make Cheesecake Filling

Beat cream cheese until smooth.

Add sugar and mix well.

Add eggs one at a time on low speed.

Mix in sour cream, vanilla, and cornstarch until just combined.

Step 4: Assemble & Bake

Pour cheesecake filling over brownie layer and smooth top.

Place pan on a baking sheet.

Bake for 45–50 minutes, until edges are set and center gently jiggles.

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

Step 5: Chill

Cool to room temperature, then refrigerate 4–6 hours or overnight.

Step 6: Make Hot Fudge

Heat cream until steaming.

Add chocolate chips, butter, and corn syrup. Let sit 2 minutes.

Stir until smooth and glossy. Add vanilla. Cool slightly.

Step 7: Decorate

Remove cheesecake from pan.

Pour hot fudge over top, letting it drip naturally.

Garnish with whipped cream, cherries, sprinkles, or nuts.