Mix all the ingredients for the layer and pour out a thin layer (up to 1/4 (7 mm)) in a greased with oil and sprinkled with flour rectangular tray, place it in a highly preheated oven.
After a while, when the layer rises, change the oven setting to medium heat. The layer is ready when a toothpick comes out dry when you poke it and it turns slightly golden red. While the cake layer is cooling, beat the butter into foam with the powdered sugar, cocoa and vanilla.
Smear the cream well on the cooled layer, cut it into small diamond shapes (with a side of 1 1/4″ (3 cm)). The rhombuses must not have very long sides, but be more square. Sprinkle with coconut flakes. Gently tap the top so the flakes don't crumble later.
Leave them in the fridge to allow the butter to harden, and only then take them out! This fudge is absolutely spectacular and there's no housewife that hasn't asked for the recipe once she's tried it.