Heat oven to 350F and line an 8x8 pan with parchment.

Whisk butter and one cup sugar, beat in two eggs, then stir in cocoa and flour.

Spread the brownie batter into the pan, reserving a few spoonfuls.

Beat cream cheese with the remaining sugar and egg, then spread over the brownie layer.

Dot with raspberry jam and reserved batter, then swirl with a knife.

Bake 32 to 35 minutes until the cheesecake is just set, then cool and chill before slicing.