Preheat oven 160°C/320°F and line 2 x 6IN / 15.24CM cake tins with baking paper, grease with oil and dust with some of the dry ingredients when it's mixed together.
Mix ground flaxseed with boiling water and mix together with a fork. Set aside so it can thicken.
In the bowl of a stand mixer with a paddle attachment, cream together butter and sugar until creamy with no lumps.
Sieve flours, cocoa, baking powder, baking soda, salt and cinnamon in a small mixing bowl. Mix with a whisk to areate and combined.
In a small jug mix coconut milk and flax egg replacer and mix well.
Add one-third of the flour mix very slowly and mix on lowest speed to the creamed butter, then add one-third of the liquid. Repeat until all ingredients are just combined. It will be a thick batter.
Whilst on the lowest speed, trickle boiling water down the side of the mixing bowl. Mix until just combined.
Divide between tins. If you want perfect layers, weigh the cake tins with batter in them. Tap tins on the bench to release air bubbles, bake 47 to 50 mins, check with a skewer through the centre, if it comes out almost clean it's ready.
Let cool in the tin for 5 minutes, then flip on a cake rake.
Level cake layers with a knife and brush or spray sugar syrup or water between layers to add moisture. This will help keep your cake moist for longer. Decorate with vegan whipped cream. I have a recipe for vegan whipped cream coming out next month.