Preheat oven to 180 degrees Celsius. Grease and flour a 6 inch round pan.
Combine almond flour, gluten-free flour, flaxseed meal, cocoa, baking powder, baking soda. In a large mixing bowl, cream together coconut sugar, coconut oil, vanilla extract, almond milk, instant coffee and apple cider vinegar. Pour dry mixture to wet and mix until combined.
Pour batter into prepared pan. Bake for 35 to 40 minutes, or until a toothpick inserted into the cake comes out clean. Cool for 10 minutes in the pan, then turn out onto a wire rack and continue cooling.
Place the margarine and peanut butter into an electric mixer. Gradually mix in the icing sugar, and when it starts to get thick, incorporate almond milk one tablespoon at a time until all of the sugar is mixed in and the frosting is thick and spreadable. Add vanilla extract and salt and bear for 2-3 minutes to get creamy and fluffy. Top frosting over chocolate. Slice and enjoy