Coffee and Walnut Cake

Ingredients for the cake:

14 g baking powder
150 g unrefined sugar
200 g all-purpose flour
1/8 tsp bicarbonate
pinch of salt
75 g chopped walnut
225 ml soy milk
9 ml apple vinegar
67 ml sunflower oil
One espresso cup of coffee

Ingredients for the coffee buttercream:

300 g vegan butter (my preference Naturlì)
400 g icing sugar
pinch of salt
Two espresso cups of coffee or more if you like

Preparation:

Preheat the oven to 175 degrees and grease the 8-inch cake tin.
Mix the soy milk with vinegar in a measuring jug and let it rest for 10 minutes.
In a bowl, mix well all the dry ingredients. Add the sunflower oil and the coffee to the milk and whisk together. Add the wet ingredients to the dry ones and mix well.
Pour the batter into the cake tin and tap the worktop container to remove any air bubbles. Bake for around 30-35 minutes.
To check the cake is ready, put a skewer in; the cake is cooked if it comes out clean.

In the meantime, make the coffee buttercream. Put the butter in a food processer and whisk at high speed until the consistency is like cream. Add sugar, coffee and a pinch of salt. Let it rest in the fridge.

Cut the cake in half horizontally. Wet the middle layers of the cake with a small amount of coffee. Spread the intermediate layers with the buttercream, sandwich them together, and cover the whole cake with the remaining buttercream. Please leave it in the fridge for 1 hour to set.

I transferred the leftover buttercream into a piping bag with a star nozzle attached to decorate it. Pipe swirls of cream onto the cake; then, I added coffee beans and walnuts.
Once ready, the cake can be either served straight away or stored in the fridge for 2/3 days.