Preheat the oven to 150℃. Grease a 15 cm cake pan, line with a parchment paper round, then grease the parchment paper.
Chop the chocolate and place it in a bowl.
Pour the cream into a pan and heat it on medium.
Pour the cream over the chocolate and stir until combined.
Add the butter and continue stirring.
Add the cocoa powder and stir it consistently until smooth.
Separate the eggs. Add the sugar to the egg yolks. Beat it until fluffy.
Pour the egg mixture it into the chocolate batter. Add the flour and stir it until combined.
Beat the egg whites into stiff peaks. Whip the egg whites into the batter.
Pour the cake batter evenly into prepared cake pan.
Bake for around 30 minutes or until the cake is baked through. To test for doneness, insert a toothpick into the center of the cake. If it comes out clean, it’s done. Avoid over-baking. The cake is thick and moist, so the center may slightly sink. That’s normal. Allow the cake to cool in the pan set on a wire rack. Cool completely before serving.