As soon as I laid eyes on this recipe, I knew I had to try it! Taking flavour inspiration from the Boston cream pie, these light vanilla sponges are filled with a vanilla custard and topped with rich chocolate frosting. Although the typical method of creaming butter and sugar together first to incorporate air isn’t used here, the cakes are amazingly airy and delicate, and as an added bonus (as if I needed to say more) they stay wonderfully moist in an airtight container for a good few days – I actually thought they tasted better the day after I baked them.
I discovered these beauties in Cake Days, a book of recipes from the brilliant Hummingbird Bakery, which you can purchase here. It’s full of really interesting flavour combinations and I can guarantee that I’ll be posting many more recipes from the book on this blog in the weeks to come!
NB: If you prefer your frosting to be less sweet, simply change the ratio of icing sugar to cocoa powder, but make sure that the two quantities should still add up to 500g.
Makes about 12-16 Cupcakes
For the sponge:
•80g unsalted butter, softened
•280g caster sugar
•240g plain flour
•1 tbsp baking powder
•¼ tsp salt
•240ml whole milk
•2 large eggs
•1 tsp vanilla extract
For the filling:
•250ml whole milk
•½ tsp vanilla extract
•2 large egg yolks
•50g caster sugar
•1 tbsp plain flour
•1 tbsp corn flour
For the frosting:
•400g icing sugar
•100g cocoa powder
•160g unsalted butter, softened
•80ml whole milk
•One or two 12-hole muffin tins
Preheat the oven to 190°C and line a muffin tin with cupcake cases.
Using a hand-held electric whisk, mix the butter, sugar, flour, baking powder and salt on a low speed until the mixture starts to look like fine breadcrumbs.
Whisk the remaining ingredients in a jug, then pour in ¾ of this mixture into the dry ingredients and mix on a low speed. Increase the speed to medium and keep mixing until the mixture becomes smooth and thick, scraping the sides of the bowl to ensure all the ingredients are incorporated. Add the remaining milk mixture and beat until combined and smooth.
Spoon the batter into the paper cases, filling them by two-thirds. Bake in the oven for 18-20 minutes or until well risen and springy to the touch, then leave to cool completely.
While the cupcakes are baking, make the filling. Pour the milk and vanilla extract into a saucepan and bring to the boil. In the meantime, whisk the rest of the ingredients by hand in a bowl until smooth and well combined.
Once the milk is boiling, remove the pan from the heat and pour 4-5 tablespoons of the mixture from it into the egg yolk mixture to loosen, then add this mixture to the pan of hot milk, stirring well.
Return the pan to the heat and bring to the boil, whisking constantly so that lumps do not form. Boil for at least a minute to make sure that the flour is cooked out completely. Once thickened, tip the custard into a bowl and leave to cool completely for 30-40 minutes.
To make the frosting, use an electric whisk to beat together the icing sugar, cocoa powder and butter at a low speed until it takes on a sandy texture. Add the milk slowly before increasing the speed to high and whisk until the frosting becomes soft and fluffy.
Using a sharp knife, make a hole in the centre of each cupcake about 2cm in diameter and 3cm deep, keeping the scooped-out pieces of sponge. Spoon the custard into the hole in each cake, then replace the sponge lid, trimming it to ensure the top is fairly level.
Smooth the frosting over the tops of the cupcakes with a a palette knife and add a swirl. Sprinkle with grated chocolate to decorate.
Let me know how you get on if you try this recipe!