Method (cake)

1. Preheat your oven to 180 degrees c fan and line a 8×8 inch square cake tin with grease-proof paper. Allow the paper to hang over the tin, this makes it easier to remove the cake when baked.
2. In a bowl, combine the dairy-free milk with the apple cider vinegar and whisk until fully combined. Set aside for 10 minutes to curdle. This creates a vegan ‘buttermilk’.
3. Mix the coffee granules and hot water in a bowl. This makes a coffee concentrate.
4. In a large mixing bowl, sift the flour, cocoa powder, sugar, baking powder and bicarbonate of soda. Mix well to combine.
5. Add the oil and coffee concentrate into the ‘buttermilk’ and whisk to combine.
6. Add the wet ingredients into the dry ingredients and mix.
7. Pour the batter into the lined tin. Use a cranked pallet knife to smooth out the batter, making sure to get it into the corners of the tin.
8. Make sure to tap the tin on the worktop one or two times to remove any air bubbles.
9. Pop the cake into the middle of the preheated oven and bake for around 20 minutes. You will know it is done when you put a knife or skewer down the middle of the cake and it comes out clean and it’s springy to the touch.
10. Allow the cake to cool in the tin for 10 minutes then carefully transfer onto a cooling rack. Allow to cool fully before frosting. You can even place the cake in a sealed container once cool then frost the day after. It’s a very light sponge so be careful with it when removing from the tin.

Method (buttercream)

1. Mix the coffee granules and hot water in a small bowl and mix until combined. This creates a coffee concentrate, which will flavour the buttercream.
2. In a large mixing bowl, add in the dairy-free butter and whip until creamy. I use a stand mixer with a balloon whisk attachment, a hand mixer will work great too.
3. Sift in the icing sugar and whip on high speed for a couple of minutes to incorporate it.
4. Pour in the aquafaba and coffee concentrate. Whip for 5 minutes until it turns light and creamy. Don’t over whip it or it can become too soft. If it does, just add in more icing sugar until it’s thick and creamy. The buttercream should be very light and airy. Add more chunks more butter to get it to the right consistency.
5. Dollop the buttercream on the sheet cake and use a cranked pallet knife / off set spatula to swirl it around.
6. Why not decorate the cake with some whole coffee beans and vegan sprinkles?! Go all out and serve it with some vegan caramel sauce.