Preheat Your Oven: Start by preheating your oven to a medium temperature (about 350°F or 175°C).
Prepare the Pasta: In a mixing bowl, beat the egg whites until they form stiff peaks. Gradually add the egg yolks, one at a time, while continuing to whisk.
Add Sugar and Flour: Carefully fold in the sugar and wheat flour, mixing gently until you achieve a smooth, homogeneous dough.
Bake the Cake: Pour the batter into a greased and floured baking pan. Spread it evenly and place it in the oven. Bake for approximately 20 minutes or until the top is golden brown.
Make the Filling: In a pan, heat 2 tablespoons of margarine, add the condensed milk and grated coconut, and stir until thickened. Once done, set it aside to cool.
Prepare the Roof: In another pan, combine the milk, chocolate powder, sugar, and the remaining margarine. Bring it to a boil, then let it simmer for about 30 minutes until it thickens, stirring occasionally.
Assemble: Once the cake has cooled, place it on a sheet of baking paper. Spread the filling onto the cake, then roll it up gently using the paper or wrap.
Top It Off: After rolling, pour the chocolate roof over the top and decorate as desired.