Serves 16-20. Total time: 50 minutes
These cheesecake brownies are, however, heart-stoppingly dense and tender.

Chocolate mixture

110 g dark chocolate (minimum 70% cocoa solids)
110 g unsalted butter
150 g caster sugar
60 g plain flour
1/4 tsp sea salt
2 medium eggs

Cheesecake mixture

225 g cream cheese
50 g caster sugar
1 tsp vanilla extract
1 medium egg

Preheat the oven to 150C fan oven/160C or 315F electric oven/Gas 2 and butter and flour a 23 cm square cake tin. Melt the chocolate with the butter in a bowl set over a pan of simmering water. Remove from the heat, add the sugar and stir, then leave to cool slightly. Sift the flour and salt into a large bowl. Add the eggs to the chocolate mixture, beating after each one until it is very glossy. Lightly fold in the flour and set aside.

Beat the cream cheese with the sugar in a bowl for the cheesecake mixture. Add the vanilla essence and egg and mix. Spread the chocolate mixture in the prepared tin evenly Top with the cheesecake mixture and using a sharp knife, gently swirl it into the chocolate mixture. Bake for 20-30 minutes, or until just set in the middle. Leave to cool in the tin for 15-20 minutes before cutting into squares and serving.