A little milkif needed to get the buttercream to the right consistency
Make the white chocolate sponges
Pre-heat your oven to 180°C/160°C fan.
Line two 20cm round sandwich tins with greaseproof paper or reusable baking liners.
Microwave your white chocolate chips (200g) for 10 seconds - you want them to be tacky around the edges, not melted.Add ½ tsp of flour to the white chocolate chips and toss the chocolate chips in the flour until they coated in it.
In a large bowl, cream together the butter/margarine (200g) and caster sugar (200g) until it's light in colour with a fluffy texture.
In a separate bowl, mix together your eggs (2 large), natural yogurt (80g) and vanilla extract (¼ tsp) with a fork until just combined.Gradually add the egg and yogurt mixture into the butter and sugar. Beat in each addition well before adding more - don't panic if the mixture starts to look a little split (thats' down to the yogurt).
Add the self-raising flour (240g) and bicarbonate of soda (½ tsp) and fold into the other ingredients.
Finally add roughly ⅔ of the white chocolate chips and fold them into the cake mixture.
Divide your cake mixture between the two prepared tins. Use the back of a spoon to spread the cake mixture evenly in the tins. Sprinkle the remining chocolate chips over the top of the cake mixture.
Bake the cakes for approximately 25 minutes, until a skewer entered into the middle comes out clean.
Once baked, leave the cakes to cool in their tins for about 10 minutes, before removing them from the tins and putting them on a wire rack to cool completely.
While your cakes are cooling, make the white chocolate buttercream
Break the white chocolate (140g) and melt it over a bain marie (in a bowl over a pan of simmering water) or in short bursts in the microwave.Once the chocolate has melted, allow it to cool to room temperature (but make sure it's still runny).
Once the chocolate has cooled, beat together the butter (175g) and icing sugar (175g) until combined.
Gradually add the melted, cooled white chocolate, beating constantly to combine it with the butter and sugar.
Check the consistency of your buttercream - it should be a soft, spreadable consistency, but not runny. If the buttercream is a little stiff, add some milk (no more that 1 tsp at a time) until you have the consistency you want.If the buttercream is a little too soft, pop it into the fridge for a short while to firm up a bit.
Once your buttercream is ready, build your cake. Place one layer of sponge onto your serving dish. Add half of the buttercream and spread it across the sponge - I use a small palette knife. Repeat with the second sponge.Add your preferred decoration - I use freeze-dried raspberries and white chocolate shavings.Enjoy!
If this is your first time making this recipe then I'd recommend having a read of the main blog post as this contains lots of extra tips as well as the answers to some recipe FAQs.