315g plain flour
1/2 tsp baking powder
1/2 ts baking soda
1/2 tsp salt
225g unsalted butter, softened
450g caster sugar
3 large eggs
1 tsp vanilla extract
1 cup sour cream (235ml)
WHITE CHOCOLATE BUTTERCREAM:
100g white chocolate
200g caster sugar
1/4 cup water
5 egg whites
1/4 cup (50g) caster sugar
450g unsalted butter, room temperature
Preheat oven to 180c
Grease and line two 8-inch cake tins, which are at least 2 inches high.
Sift together the flour, baking powder, baking soda and salt.
In a mixer cream the butter and sugar until fluffy.
Add the eggs, one at a time, beating well after each addition.
Stir in the vanilla.
Add half the dry ingredients, and stir until combined. Then add the sour cream and stir until fully incorporated. Lastly, add the remaining dry ingredients, and stop stirring as soon as they are incorporated.
Scrape batter evenly into the prepared cake pans, and level the surface.
Bake until the centre springs back lightly when pressed, about 40 minutes.
Let the cakes cool in the pan, then invert onto a rack.
N.B. You will need 2 or 3 batches of this recipe for a large celebration cake.
White Chocolate Buttercream:
Melt the white chocolate, either in the microwave or over a bain-marie.Boil 200g of sugar and 1/4 cup water over medium-high heat, without stirring, bruising down the sides of the pan occasionally, until it reaches 118c.
As it cooks begin meringue so it's ready when syrup is done. Whisk the egg whites in a mixer until they become foamy, then add the 1/4 cup of sugar, gradually.
Carefully pour the hot syrup into the meringue in a steady stream with the mixer still on high speed. Beat the meringue for 10 minutes until the outside of the bowl is room temperature.
Gradually add the butter in small pieces, and continue to beat until the buttercream is smooth. Add the cooled melted chocolate, and beat again to incorporate.