Line an 8x8-inch baking pan with non-stick aluminum foil or parchment paper. Pour green batter into pan. Smooth out surface. Bake for 10 minutes. This cake will be just a bit under baked, and that is what you want. Remove the cake from the pan using the foil as handles. Set on a wire cooling rack. Allow cake to cool for 15 minutes, then place in freezer for 15 minutes.