Prepare the Blackberry Swirl

Cook the Blackberries: In a small saucepan, combine the blackberries and 2 tablespoons of sugar. Cook over medium heat, stirring occasionally, until the blackberries break down and the mixture thickens, about 5-7 minutes. Mash the berries with the back of a spoon as they cook. Remove from heat and let the mixture cool slightly, then strain it through a fine mesh sieve to remove the seeds. Set the blackberry sauce aside.

Make the Brownie Layer

Preheat Oven: Preheat your oven to 350°F (175°C). Grease an 8x8-inch baking pan or line it with parchment paper, leaving an overhang for easy removal.

Mix Wet Ingredients: In a large mixing bowl, whisk together the melted butter, sugar, eggs, and vanilla extract until smooth and well combined.

Add Dry Ingredients: Add the cocoa powder, flour, salt, and baking powder to the wet ingredients. Stir until just combined, being careful not to overmix.

Spread the Brownie Batter: Pour the brownie batter into the prepared baking pan, spreading it out evenly.

Make the Cheesecake Layer

Beat the Cream Cheese: In a separate mixing bowl, beat the softened cream cheese and 1/4 cup sugar together until smooth and creamy.

Add the Egg and Vanilla: Beat in the egg and vanilla extract until fully incorporated.

Layer the Cheesecake: Pour the cheesecake mixture over the brownie batter in the pan, spreading it into an even layer.

Add the Blackberry Swirl

Swirl the Sauce: Drop spoonfuls of the blackberry sauce over the cheesecake layer. Use a knife or skewer to gently swirl the sauce into the cheesecake layer, creating a marbled effect.

Bake and Serve

Bake: Bake in the preheated oven for 30-35 minutes, or until the cheesecake layer is set and the edges are lightly golden. A toothpick inserted into the center should come out with a few moist crumbs, but not wet batter.

Cool: Allow the brownies to cool completely in the pan on a wire rack. Once cooled, use the parchment paper overhang to lift the brownies out of the pan and onto a cutting board.

Serve: Slice into squares and serve. Store any leftovers in an airtight container in the refrigerator.