Mango Mousse Slices

For the cake: heat the oven to 170°C (150° fan) 325°F gas 3. Grease a deep 17 12/cm|7" square baking tin and line the base with non-stick baking paper.

Whisk together the egg whites and 40g|1 1/2oz of sugar in a mixing bowl. Add the cream of tartar and whisk until stiff but not dry.

In another bowl, whisk together the egg yolks and remaining sugar until pale and fluffy.

Add the vanilla, milk and oil to the egg yolk mixture, then sift in the flour and bicarbonate of soda and fold in gently.

Fold the egg yolk mixture into the egg white mixture.

Put into the tin and bake for 30-35 minutes until a skewer inserted into the centre comes out clean. Cool in the tin, then slice horizontally into 2 slices and trim them into a 16cm|6 1/2" square.

For the mango mousse: whisk together the cream and icing sugar until thick. Chill.

In a small bowl, dissolve the gelatine in hot the water. Stir into the mango puree and mix well.

Add the mango mixture to the cream. Mix well until incorporated.

Place a layer of cake in the tin and pour in enough mango mousse to cover. Add the chopped mango and cover with more mousse. Chill for 10 minutes.

Place the remaining cake layer on top and top with the remaining mousse. Chill for 30-45 minutes until set.

For the topping: dissolve the gelatine in the hot water. Stir in the mango puree and set aside to cool but not set.