White and Dark Chocolate Squares

Heat the oven to 180°C (160° fan) 350°F gas 4. Butter a 23 cm| 9"square tin.

Put the plain and white chocolates into two separate heatproof bowls and add half of the butter to each. Melt over a pan of simmering (not boiling) water. Stir until the chocolate and butter are blended.

Add 150 g sugar and 2 beaten eggs to each bowl, then beat until smooth.

Stir 50 g of the flour into the plain chocolate mixture and the remaining 90 g into the white mixture.

Spoon tablespoons of the mixture into the tin, alternating plain and white chocolate to make a patchwork pattern. When the base of the tin is covered, spoon more mixture over the first layer, spooning white on top of the dark mixture. Drag a skewer through the tin several times to create a marbled effect.