1 cup unsalted butter (2 sticks), melted
1 cup milk or semi-sweet chocolate chips (optional)
5 large eggs
2 1/3 cups granulated sugar, divided
1 tablespoon vanilla extract
1 1/2 cups all-purpose flour
1 cup cocoa powder
1 teaspoon baking powder
8 ounces cream cheese, softened
1/3 cup sour cream
1/4 teaspoon baking soda
1 cup caramel sauce, plus extra for serving if desired (optional: salted caramel sauce)
Vanilla ice cream, for serving (optional)
Preheat oven to 350°F. Line a 13-by-9-inch baking dish with parchment paper, leaving excess to assist with removal.
Beat 4 eggs in large bowl with 2 cups sugar, melted butter and vanilla extract. Add flour, cocoa powder and baking powder, mixing to form a thick batter. Optional: fold in chocolate chips. Transfer batter to prepared baking dish.
Beat remaining egg with cream cheese, sour cream, baking soda and 1/3 cup sugar. Pour cream cheese mixture over brownie batter.
Generously drizzle caramel sauce over cheesecake layer. Use a knife or small spatula to swirl ingredients, creating a marbled appearance.
Bake in preheated oven 25 to 30 minutes until toothpick inserted in center comes out clean. Cool completely.
Remove brownies from pan using excess paper as handles. Cut into squares and enjoy!