Lightly grease a 9-inch springform pan and line the bottom with parchment. Preheat the oven to 350°F (175°C).

Prepare the brownie batter according to the package directions or using your favorite homemade recipe.

Spread the brownie batter evenly in the prepared pan and tap it gently to level it.

Bake the brownie layer for about 15 minutes, until set around the edges but still soft in the center.

Let the brownie layer rest for 10 minutes while preparing the cheesecake filling.

In a mixing bowl, beat the cream cheese until smooth.

Gradually add the sugar and salt; mix well.

Add the vanilla extract and sour cream, mixing until glossy.

Add the eggs one at a time on low speed until just combined.

Pour the cheesecake mixture over the warm brownie base and smooth the top.

If desired, wrap the pan with foil and place it in a larger pan with hot water halfway up the sides.

Lower the oven temperature to 325°F (163°C) and bake for 40-50 minutes until edges are set and the center jiggles slightly.

Turn off the oven, crack the door, and let it sit for 30 minutes. Then cool completely on the counter and chill for at least 4 hours, preferably overnight.

Decorate the cheesecake with whipped cream, fresh berries, chocolate shavings, or caramel.

Use a warm knife for clean slices.