Preheat oven to 200C/180C fan, and line your baking dish with baking paper.Tip the grated courgette in a sieve and squeeze to remove excess moisture.In a bowl, whisk together the ground almonds, cacao, baking powder, coconut sugar and salt. Set aside until ready to use.In another bowl, mix together yoghurt, coconut oil and chia eggs.Mix both bowls together and stir until well combined.Tip in the grated courgette and raw chocolate if using.Pour the batter into the prepared baking dish and bake for about 45 minutes or, until a toothpick inserted into the centre comes out clean.Allow to cool completely before cutting into slices.