Rhubarb & custard cake
The upside of baking your own birthday cake is that you get to have exactly the cake you want. The downside of baking your own birthday cake is baking your own birthday cake!
I don’t actually mind to be honest, the kitchen is my happy place, so it’s no real chore to spend an hour or so in there creating a delicious treat to share with my friends.
I’ve adapted my recipe for fresh peach buttermilk cake for this. It makes such a lovely bouncy sponge and adding some tart (homegrown) rhubarb makes me love it even more than the original. The rich, creamy custard buttercream is quite literally the icing on the cake. So good!
50ml of vegetable/sunflower oil
300g plain flour
2 tsp baking powder
1 tsp bicarbonate of soda
2 tbsp plain flour
70g custard powder
200g room temperature butter, cubed
Grease and line a 9″ square cake tin and pre-heat your oven to 190°c.
Dice the rhubarb and toss it in 25g of the sugar. Roast the rhubarb in the oven as it pre-heats, until it is just tender.
Beat together the oil, sugar and salt until they are thick and pale. Beat in the eggs, one at a time. Sift together the flour and raising agents. Add one third of this to the batter and briefly beat it in. Follow this with one third of the buttermilk and beat again. Repeat this until all of the flour and buttermilk have been incorporated and you have a thick, smooth batter. Drain off the juice and fold the rhubarb through the batter. (Don’t throw the juice away – it’s delicious added to a gin and tonic) Pour the batter into the prepared tin and use a spoon to spread it out and smooth off the top.
Bake the cake for around 30 minutes, until a cake tester comes out clean and then leave it to cool in the tin for a few minutes before turning it out onto a wire rack to cool completely.
You can start to make the frosting whilst the cake bakes. Combine everything but the butter in a pan, making sure that there are no lumps. Gently heat the mixture until it turns into a very thick paste. Leave to cool.
Once the custard mixture has cooled transfer it to the bowl of a stand mixer and beat it until it starts to become a little fluffy. Add the butter, a few pieces at a time, with the mixer running, until you have a rich thick, creamy buttercream. Either spread or pipe this onto the cooled cake, depending on how fancy you’re feeling!