In a large bowl, place all dry ingredients except cocoa (flour, ground almonds, flaxseeds, baking powder, coconut sugar) and mix them.
In another bowl, mix the wet ingredients (vanilla extract, agave syrup, herbal tea, oil and coffee) and add them to the dry ingredients mixture.
Mix with a hand mixer until smooth.
Pour half of the mixture into a 25 cm diameter cake tin and bake for 25 minutes in a preheated oven at 180 °C.
Stir in the cocoa powder into the other half of the mixture, mix well and pour into a 25 cm diameter cake tin and bake for 25 minutes in a preheated oven at 180 °C.
Place the sponge cake on a cooling rack and leave to cool. If the top of the sponge cake is rounded, cut it off so that the cake is nice and flat when you put it together