Preheat the oven to 180°C.
Line an 8 inch diameter cake tin with parchment paper.
Heat up the water and add the coffee powder. Let the coffee infuse for a while.
Pour the black coffee into a small bowl. If it has become cold, heat it up again.
Add cocoa powder and the grated chocolate to the hot black coffee.
Stir till the chocolate melts.
Add oil, vinegar, sugar and mashed avocado to the black coffee mixture and whisk.
In another bowl sift or sieve flours, salt, baking powder, baking soda, cinnamon powder and red chilli powder together.
Add the liquid mixture to the dry flour mixture.
Fold in gently till all the flour mixture is wet. Don't over mix the batter.
The batter will be a bit runny.
Pour the batter into the prepared tin. Smoothen the top with a spatula.
Bake the cake for 45 -55 minutes or till a skewer or toothpick inserted in the middle of the cake comes out clean.
Allow the cake to cool down in the tin for 10 minutes.
Remove the cake from the tin, peel off the parchment paper and allow the cake to cool down competely on a wire rack.