Preheat your oven to 350°F (175°C) and grease a 9-inch springform pan. If using a brownie mix, prepare according to the package instructions. For homemade, melt butter and chocolate in a saucepan, then mix in sugar, eggs, and vanilla. Pour the brownie batter into the pan and bake for 25–30 minutes, or until a toothpick comes out with a few moist crumbs. Let it cool completely in the pan.

In a mixing bowl, beat 16 ounces of room temperature cream cheese until creamy, about 2 minutes. Add ½ cup sour cream, ½ cup sugar, and 1 teaspoon vanilla extract, blending until smooth. Make sure there are no lumps, as this will ensure a silky texture. Pour the cheesecake mixture over the cooled brownie base, spreading it evenly.

Reduce the oven temperature to 325°F (163°C) and bake the cheesecake for 50–60 minutes. It should appear set around the edges but slightly jiggly in the center. Keep an eye on it to prevent overbaking, as it can crack. Once done, remove it from the oven and let it cool to room temperature before transferring it to the refrigerator; chill for at least 4 hours or overnight for best results.

After chilling your Ultimate Hot Fudge Sundae Brownie Cheesecake, prepare your hot fudge sauce. You can use store-bought sauce or make your own by heating heavy cream and chocolate chips together until melted and smooth. Once ready, drizzle the warm fudge over the top of the cheesecake, allowing it to pool slightly around the edges for that decadent look.

Before serving, whip up some heavy cream until peaks form for a light topping. Generously dollop the whipped cream on top of the fudge, then add a sprinkle of colorful sprinkles and a few maraschino cherries for a classic sundae touch. Cut into slices and enjoy this indulgent Hot Fudge Brownie Cheesecake that’s sure to impress friends and family alike!