Preheat the oven to 180 ° C.
Separate the whites from the yolks.
Mix the yolks with the sugar and beat until the mixture turns white.
Add the flour, almond powder and butter. Mix.
Whisk the egg whites and gently fold into the mixture.
Pour on a baking sheet covered with a sheet of parchment paper, spread out well to have a nice rectangle. Bake for about 12 minutes.
Remove from the oven and immediately place a new sheet of parchment paper on the sponge cake, another plate and turn over to have the sponge cake in the new plate on the new sheet.
Carefully remove the baking sheet that was used for cooking.
Gently roll the sponge cake with the new sheet of paper. Then let cool.