Mix the flour, ground almonds, baking powder, salt, and sugar in a mixing bowl. In a separate bowl, combine the mashed banana, vanilla extract, coconut oil, apple cider vinegar and almond milk. Add the wet ingredients to the dry ingredients and combine.
Pour the cake batter in a lightly oiled loaf pan.
Place the cake in the oven for about half an hour. Use the toothpick method to check if your cake is baked all the way through.
When the cake is cooled off, heat the chopped chocolate in a double boiler (or microwave) and add the coconut oil.
Coat the cake with the chocolate and top it with sliced almonds. Refrigerate the cake for about an hour until the chocolate coating is hardened before serving.