Crumble dough. Chop up the cold ■ margarine into small pieces, then use a fork to lightly mix it up into the ■ sugar, flour, and cocoa powder. Place into the refrigerator to chill.

Once it becomes cool and hard, use your hands to lightly mix it so that it becomes crumbly, then chill again.

Put the chocolate and margarine in a heatproof bowl and heat in the microwave for one minute to melt. Mix in the egg yolks.

Whip the egg whites, adding the sugar as you go. Continue to whip until stiffened.

Add the heavy cream and sifted dry ingredients into Step 3 and mix.

Divide the meringue into three parts and mix in one part at a time into Step 5. Use a whisk for the first two parts, then use a rubber spatula to fold the third part in. Add the chopped walnuts and mix.

Pour the batter into a cake pan greased with margarine. Drop the pan onto a table a few times to break air bubbles in the batter. Top with the crumbles from Step 2. Put leftover crumbles in the refrigerator to use next time.

Bake in an oven at 180°C for 30 minutes. I dusted powdered sugar over a plate topped with a kiri-e (Japanese paper-cutting art) to make a decoration on the plate, then put the cake on top.