Preheat the oven to 180°C/Fan, Gas Mark 4. Oil a 25cm round cake tin and line it with non-stick baking paper. Start with the cake. Break the chocolate into a heatproof bowl and set it over a saucepan of simmering water until melted (make sure the bowl does not touch the water). Set aside to cool slightly.
In a bowl, combine the flour, baking powder, bicarbonate of soda, ground almonds, cocoa and coconut and mix well. In a separate large bowl, whisk the oil and sugar for a minute with an electric whisk until smooth. Add the eggs and whisk until combined.
Add the melted chocolate and beetroot to the cake batter with the vanilla and mix well. Now add the dry ingredients and fold them all in, making sure everything is mixed well. Pour the cake batter into the prepared tin and bake for 55–60 minutes until a skewer inserted comes out clean. Leave the cake to cool in the tin for 10 minutes, then turn it out and place on a wire rack.
Meanwhile, prepare the ganache. Without shaking the can of coconut milk, open it, scoop out the solids and add them to a saucepan. Heat until they start to bubble. Put the chocolate in a heatproof bowl, pour the hot coconut milk on top and stir until the chocolate melts.
Once the cake has cooled, transfer it to a serving plate, pour the ganache on top and serve warm, or wait until the ganache has set slightly. Store in an airtight container in the refrigerator for 3–4 days. You might want to warm the slices in the microwave for 10 seconds before serving.