Delia recipe and doesn't take long at all. Sponge cake.
6oz self-raising flour
1 rounded teaspoon baking powder
3 large eggs
6oz caster sugar
6oz butter, very soft (room temperature)
1/2 teaspoon vanilla extract
Mix butter and sugar together in a bowl
Add the eggs
Gradually sieve in flour/baking powder and beat to get good consistency
Add vanilla extract and mix
Split between two baking tins (8") and bake in oven 170C (325F) for 20 mins or until brown on top and cooked in middle (use wooden skewer to test - if cooked it will come out 'clean', ie: no cake mixture stuck to it).
For the filling:
Raspberries, or strawbs or bluebs or anything you like
1 x 250g tub mascarpone cheese
1 x 200ml tub fromage frais
1 x level tbsp caster sugar
1 tsp vanilla extract
Mix mascarpone and fromage frais together, add sugar and vanilla extract.
Slather raspberry or strawberry jam onto one side of each cake, slather the filling on top of the jam, arrange the raspbs in a pretty pattern on one cake, put the other cake on top and sandwich together. To finish, lightly dust (use a tea strainer) with icing sugar.