01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or grease thoroughly with butter or cooking spray.
02 - Melt the butter in a medium microwave-safe bowl or saucepan. Whisk in the granulated sugar and brown sugar until the mixture appears glossy and well combined. Beat in the eggs and vanilla extract until smooth.
03 - Sift the cocoa powder, flour, and salt directly into the wet mixture. Fold gently with a spatula until just combined—be careful not to overmix, which can make the brownies tough.
04 - Divide the brownie batter evenly among the 12 prepared muffin cups, using about 1 heaping tablespoon per cup. Use the back of a spoon to spread the batter evenly in the bottom of each liner.
05 - In a separate clean bowl, beat the softened cream cheese with an electric mixer until completely smooth and creamy. Add the sugar, egg, and vanilla extract. Continue beating until the mixture is lump-free and well incorporated.
06 - Soon approximately 1 tablespoon of the cheesecake filling over each brownie base. Gently smooth the tops with the back of the spoon to create an even layer.
07 - Generously sprinkle each cup with your choice of loaded toppings. Press them lightly into the cheesecake layer to ensure they adhere during baking.
08 - Bake for 22 to 25 minutes, or until the cheesecake filling is set and the edges of the brownie cups appear firm. The centers should still have a slight jiggle.
09 - Allow the cups to cool in the muffin tin for 10 minutes. Carefully transfer to a wire rack to cool completely to room temperature. For the best texture and flavor, refrigerate for at least 1 hour before serving.