Grease and flour a 20 cm (8-inch) round pan, about 2 inches deep. You can use a 22 cm (9-inch) pan, but the cake will be slightly less tall.

Melt the chocolate (in chips or chopped into small pieces) with the butter cut into cubes, using a double boiler or the microwave. For the double boiler, place everything in a heatproof bowl set over a saucepan with a little simmering water. Once melted and smooth, let it cool.

Beat the eggs and sugar for about 10 minutes, until pale and tripled in volume.

Add the sifted flour in 3 to 4 additions, gently folding it in from the bottom up without whisking. Tap the whisk against the sides of the bowl from time to time.

Add the melted chocolate and butter mixture, cooled to lukewarm or cold, and fold it in the same way, gently, to avoid deflating the batter and keep it light and airy.

Pour the batter into the pan, gently tap it on the counter, and smooth the top.

Bake for 35 to 45 minutes. I used a smaller pan than recommended, so the cake took longer to bake as it was thicker.

Check for doneness with a skewer inserted in the center. It should come out clean. If not, continue baking. If the top starts to brown too quickly, cover it loosely with aluminum foil.

Remove the pan from the oven and let the cake rest for about 10 minutes before unmolding. Run a knife around the edges, then gently invert the cake onto a plate. Turn it over onto another plate carefully to avoid damaging the crackly top.

You can enjoy it slightly warm, but it’s even better once completely cooled, and even more f