Vanilla sponge (recipe from Cooks Illustrated) 220gr plain flour 30gr cornflour | 2 1/4 cups cake flour 240 ml | 1 cup whole milk, at room temperature 6 large egg whites at room temperature (180ml | 6 fl oz liquid egg whites) 1 tsp almond extract 2 tsp vanilla extract or seeds from 1 vanilla pod 395gr | 1 3/4 cups caster sugar 4 tsp baking powder 1 tsp table salt 170gr | 1 1/2 sticks unsalted butter at room temperature cut into small cubes Italian buttercream (adapted from Tea with Bea) 6 large egg whites at room temperature (180ml | 6 fl oz liquid egg whites) 360g | 1 3/4 cups caster sugar 100ml | 1/2 cup water 1 tbsp golden syrup (prevents sugar from crystallising) 500g | 4 1/3 sticks unsalted butter* at room temperature cut into big pieces Add enough of the berry reduction to achieve desired colour Pink food colouring (optional - if you want to boost the pink colour) Flavouring for buttercream 500g | 17.6 oz bag of mixed frozen berries 100g | 1/2 cup caster sugar 50ml | 1/4 cup water To make the cakes, preheat oven to 180 C | 350 F. Pour milk and egg whites and vanilla into a measuring cup and whisk briefly to combine. Put the flour, sugar, baking powder, and salt in bowl of electric mixer and mix at very low speed to combine the ingredients. Add the butter and beat a low speed until mix resembles coarse sand. Add 1/3 of the milk/egg liquid and beat to combine for about a minute. Repeat with remaining liquid but do not overmix. Divide batter evenly between 3x20cm/8inch prepared cake pans and level. Bake for 20-25 minutes. Cake will be coming away from sides of cake tin and be firm on top when ready. Cool completely before frosting. To make the berry reduction, put all the ingredients in a pot and bring to the boil (you don't have to defrost the berries first). Reduce the heat slightly and continue to cook for 15-20 minutes until the sauce is reduced somewhat. Sieve the berries and press down to extract as much juice/pulp as possible. The sauce should not be too liquid or it will spoil the buttercream. Make sure you cool it before using. To make the Italian buttercream, put the sugar and water in a pan and clip on a sugar thermometer. Bring the sugar and water to the boil. Put the egg whites in the bowl of your stand mixer (make sure it's clean without a trace of grease). When the temperature reaches 110C (230F) start whisking your egg whites till you get a nice meringue. Keep an eye on the sugar thermometer and when the sugar reaches 120C (248F) take off the heat. Pour the sugar syrup very carefully down the side of the mixing bowl in a steady stream. Keep whisking till the bowl has cooled somewhat, then start adding the butter, a chunk at a time. Keep adding the butter and pay attention to the texture of the buttercream. It may turn liquid at first, then curdle a bit - keep whisking and it will come together. Once you have glossy peaks, add the berry reduction, a little at a time, while whisking on high. You may want to add a touch of pink food colouring if you want the buttercream to be a vivid pink. Sandwich your cake layers with some buttercream and add a thin layer of frosting all over the cake. Chill for 30 minutes, then either pipe or smooth buttercream over the cake. I used a piping back with a large star nozzle to do rosettes on top of the cake.