Preheat the oven to 180C. Line a 6" tin and a 4" tin with parchment.

In a large bowl, add all the ingredients and give them a good whisk.

Divide the batter between the tins {about 170g in the 6"/ 90g in the 4" tin}. Bake for 15-20 minutes, until the tester comes out clean. Cool completely, then trim the tops.

Stir together, and leave in the pan to macerate.

Simmer over very low heat until the raspberries break down and thicken slightly. Strain out about 1 tsbp to colour the frosting if you like. Reserve.

Place the cream, sugar and agar agar in a saucepan and whisk until smooth. Simmer over low heat for 2-3 minutes stirring often to activate the agar agar.

Pour this over the white chocolate and leave until the chocolate melts. Whisk until smooth.

Whisk in the mascarpone just before you need to pour it in.

Divide into 2, approx 270g each.

Layer 1 - Stir in the raspberry compote into one half, then blend with an immersion blender.

Layer 2 - Whisk the scraped vanilla bean into the other half.

Secure an acetate sheet snugly around the 6" orange sponge. Moisten with Cointreau.

Pour over the raspberry mascarpone filling. Place the 4" sponge in the centre of the filling and very gently push in a little. Moisten the small sponge with Cointreau, then pour the vanilla bean filling over to cover it completely.

Place in the freezer for 3-4 hours until frozen, then peel off the acetate sheet and leave in the fridge overnight.

Frost with mascarpone if desired.