A rich, moist gluten-free banana cake that keeps well and improves in flavour over time. This easy recipe makes a banana cake that is perfect for cake decorating, iced with your choice of buttercream or ganache, or for eating by yourself in bed with a fork.
Line the sides of a 7" round cake pan with a tall collar of baking paper and line the base with a circle of baking paper too.
Sift the gluten free flour, baking soda and xanthan gum into a medium bowl, and whisk to combine well. Set aside.
Mash the bananas well, and weigh out 480g - 500g. Set aside.
Beat together the butter, sugar and vanilla extract using a stand mixer or handheld electric mixer until light and fluffy.
Whisk together the eggs in a small bowl or jug, then add them gradually to the butter mixture, mixing to combine between each addition.
Add in roughly half of the dry ingredients and half of the mashed banana, and mix on low speed to combine. Add the other half of the dry ingredients and mashed banana, and mix again on low speed.
Mix in the sour cream until just combined, scrape down the sides of the bowl and give it one last stir by hand to make sure it's all combined.
Working quickly, pour the batter into the prepared cake pan, and smooth the top.
Bake for 1hr, 15 - 1hr, 30 minutes, or until a skewer inserted into the centre of the cake comes out clean. If you're not sure, see this post for tips on checking if a cake is done.
Let the cake cool for at least 30 minutes before carefully removing it from the pan and transferring it to a wire rack to finish cooling.
Banana cake improves in flavour after a couple of days. To store the cake, wrap it in plastic wrap and place it into an airtight container.If you want to freeze the cake, pop the airtight container into the freezer and freeze for 2-3 months. Allow it to defrost while still wrapped and in the container, to keep the moisture in.
Fill and decorate the banana cake as desired.
Notes
Gluten free flour - I use my favourite homemade gluten-free flour blend, but you can use your own favourite store-bought or homemade blend. If you use a different flour than I do, your results may not be exactly the same as mine, but it is a forgiving recipe so it should work well with most flours. If you're using a store-bought flour blend, check the ingredients list to see if it contains a gum ingredient (usually xanthan or guar gum). If it does, you can omit the xanthan gum from the recipe.Banana - I have given a weight range of 480-500g of banana in this recipe because bananas vary in weight and I don't like wastage. Any amount between these two weights will work just fine.
Decorating the Cake
To decorate the gluten free banana cake in this post, I used 850g of dark chocolate ganache (630g dark chocolate + 220g cream) and 650g of white chocolate ganache (520g white chocolate + 130g cream). I tinted the white chocolate ganache yellow using Colour Mill 'lemon' oil-based colouring.A cream cheese frosting or a buttercream like salted caramel meringue buttercream would also be amazing with this cake.Whichever icing you choose, make sure you check that all the ingredients are gluten free!