Line a brownie tin with greaseproof paper and preheat the oven to 180°/gas mark 4.

Melt the chocolate and butter together in a heat-proof bowl over a pan of simmering water, until totally melted.

Weigh out the sugars, and combine with the buttery chocolate mixture in a large mixing bowl.

Add the flour and mix well.

Crack the eggs straight into the mixture and beat together. When you've finished, the batter should be smooth and well combined.

Pour the brownie mixture into the prepared tin, make sure it is level and leave to one side.

Now prepare the raspberry puree. Add the raspberries, 50ml water and raspberry jam (optional) into a small saucepan. Bring to the boil and bubble for 5-7 minutes until thickened and pulpy, stirring and squatting the berries occasionally to encourage them to break down. Strain through a sieve into a small bowl (discard seeds). Set aside to cool.

In a medium bowl, beat the cream cheese until soft then mix in the egg and sugar until smooth.

Pour the cheesecake mixture evenly over the brownie mixture. Gently spread to cover.

Using a teaspoon, dollop drops of raspberry puree onto the cheesecake mixture. Run a skewer through the raspberry droplets to create a marble. Once you are happy with how it looks, bake for 25-30mins or until the cheesecake looks like it has set. Cool completely before cutting into squares.