Raspberry Jam:

In a small saucepan, combine raspberries, sugar, and lemon juice. Simmer over medium heat until berries have broken down, mixture has thickened, and temperature reaches 106° C / 225° F on a candy thermometer. Alternately, you can do a manual test to see if jam stage has been reached (see notes below). Set jam aside to cool while preparing your brownie and cheesecake mixtures.

Dark Chocolate Brownie:

Preheat oven to 330° F / 165° C. Line an 8×8-inch / 20 x 20-centimeter square baking tin with parchment, grease lightly with butter or cooking spray, and set aside.

Melt butter in a saucepan over medium heat. When butter has melted, whisk in sugar, cocoa powder, and salt. Remove from heat and let cool slightly, about five minutes. Mixture will be thick.

Transfer butter-sugar-cocoa mixture to a large mixing bowl. Add eggs and vanilla to butter-sugar-cocoa mixture, and whisk to combine.

Fold in the flour, followed by the chopped dark chocolate.

Set batter aside while you prepare your cream cheese swirl.

Cream Cheese Swirl:

Add softened cream cheese to a mixing bowl or the bowl of a stand mixer, and beat on high until light and fluffy.

Beat in sugar, followed by egg yolk and vanilla, and continue mixing until well combined.

Layering the Brownies:

Spread 2/3 of the dark chocolate brownie batter into prepared tin.

Drop teaspoonfuls of the cheesecake mixture over the top, and use a knife or skewer to swirl cream cheese into the brownie batter.

Drop teaspoonfuls of raspberry jam over top of the cheesecake, and use a knife or skewer to swirl.

To finish, drop spoonfuls of the reserved chocolate batter over the top.

Bake in preheated oven for 45 minutes, or until a toothpick or cake tester comes out clean.

Transfer tin to a wire rack and allow brownies to cool completely prior to serving. Store leftovers in an airtight container at room temperature for up to three days.