Not gonna lie, I chose the ingredients for this cake based on the fact that I liked the alliteration of 'blueberry banana buckwheat'; so it's a good job that they turned out to be delicious together! I'd had a bag of buckwheat flour sat in the cupboard for a while that I had been meaning to bake with, and a couple of over-ripe bananas in the fruit bowl just begging to be made into cake. The resulting banana buckwheat cake was delicious as is, but I couldn't resist fancying it up a bit with the addition of vanilla mascarpone cream, jam and fruit. As mentioned above, I chose blueberries purely for the alliteration, and they worked perfectly, but strawberries, raspberries or a combination of the three would all also work just as well.
The combination of the buckwheat flour and banana makes for a very moist cake, it is not a light fluffy sponge but it does have a nice texture and is full of flavour. A bonus to using buckwheat flour is that this cake is gluten-free (so long as you use GF baking powder and make sure that the flour you use is certified gluten-free). I baked the cake in two deep 15cm (6in) round tins, and then split each layer in half to make a four layer cake. You could also bake the cake in two 18-20cm (7-8in) tins to make a two layer cake, though bear in mind that they will probably cook a little quicker. I sandwiched the layers together with blueberry jam, though you can use any flavour you like, and a delicious vanilla mascarpone cream frosting, which works perfectly as it is not too sweet and is so quick and easy to make.
This blueberry banana buckwheat layer cake would make a fantastic end-of-summer (sob!) celebration cake; or seeing as bananas are available all year round you can simply vary the fruit on top according to what's in season. I think that the sponge would also work well with the addition of a bit of cinnamon and nutmeg to give it a bit more of an Autumn/Winter flavour; in which case I would probably swap the jam for caramel... I'm going to have to make another one to try that combination now!
Blueberry Banana Buckwheat Layer Cake
- 220 g (7.75 oz) softened butter
- 220 g (7.75 oz) caster sugar
- 220 g (7.75 oz) buckwheat flour
- 2 tsp baking powder
- 3 large eggs
- 1 tsp vanilla extract
- 2 medium very ripe bananas - about 260g mashed
- 250 g (9oz) full fat mascarpone
- 80 g (3oz) icing sugar sifted
- 150 ml (½ + ⅛ cup) double or whipping cream (heavy cream)
- ½ tsp vanilla bean paste
- 1 jar blueberry jam
- fresh blueberries
- Preheat the oven to 180C/350F/gas mark 4. Grease two deep 15cm/6in round tins and line the bases with baking parchment.
- Beat together the butter and sugar with an electric mixer until very light and fluffy. In a separate bowl sift together the flour and baking powder. Whisk the eggs into the butter mixture one at a time, adding a spoonful of the flour with each one and beating well after each addition.
- Fold in the rest of the flour with a spatula then fold in the vanilla extract and mashed banana. Divide the mixture between the tins, level and bake for 35-45 minutes until a skewer inserted into the center comes out clean. Allow to cool in the tins for about 10 minutes then turn out onto a wire rack and leave to cool completely.
- Mix together the mascarpone and icing sugar in a bowl. Add the cream and vanilla paste and whisk with an electric mixer until smooth and the mixture forms stiff peaks, be careful not to overmix. Transfer to a piping bag fitted with a large open star nozzle and refrigerate until needed.
- Trim the tops of the cakes to level them then split each cake in half using a cake wire or sharp serrated knife. Place one cake layer on a cake stand or serving platter, spread over a couple of spoonfuls of blueberry jam then pipe dollops of the mascarpone cream on top; top with another cake layer and repeat until you have used all four layers. Spread jam over the top of the cake and pipe on the mascarpone cream, top with a couple of handfuls of fresh blueberries.
- Best served on the day it is made and keep refrigerated.
If you are making this as a gluten-free cake, make sure that the buckwheat flour you use is certified gluten-free, and that the baking powder is also a GF variety.