Prep: Measure out the ingredients. Separate the egg whites and yolks. Bring the butter to room temperature. Chop the chocolate. Sift the dry ingredients.
Coat the cake pan with butter and line with parchment paper. Preheat the oven to 170°C.
Melt the chopped chocolate over a double boiler. (If you leave some chunks, you can enjoy the same cake with a bit of a twist).
Remove from the double boiler and melt the butter into the melted chocolate.
Add the granulated sugar to the egg yolk and beat until it turns pale and thick.
Pour the chocolate into the egg yolk and stir.
Stir the sifted dry ingredients into Step 6. Don't knead the batter, just stir it roughly.
Add some salt to the egg whites and make the meringue (if any of the tools you use to make the meringue contain oil or water, the egg whites won't foam, so be careful).
Place 1/3 of the meringue into the chocolate batter and stir together without kneading. Add the remaining meringue using 2 batches. Mix without breaking the air bubbles.
Pour the batter into the cake pan and bake for 30-35 minutes in an 170°C oven.
Once you can poke the center with a skewer and have nothing stick to it, it's done.
After the cake has cooled, remove from the pan. Remove the parchment paper and let the cake cool on a cooling rack. Once it has cooled completely, optionally dust with sugar. Serve.
Story Behind this Recipe
Since my family loves gateau au chocolat, I researched various recipes that don't require heavy cream and that can be made easily with ingredients already on hand, and came up with this recipe!
Stir the meringue so that the air bubbles do not pop. Don't worry so much. The cake will be nice and fluffy if you have it the day it's baked. If you let it sit in the refrigerator for 1 day, it will taste just like the rich gateau au chocolat from a cake shop.