Separate the egg yolks from the egg whites. Beat the egg whites with 1 1/2 tablespoons (20 grams) of sugar until stiff peaks form.

Preheat the oven to 340°F (170°C). In a bowl, combine all the dry ingredients: almond flour, potato starch, cocoa powder, baking powder, chopped chocolate, and salt.

In another bowl, beat the butter with the sugar. While beating, add the egg yolks one at a time. Add the dry ingredients to the mixture along with a few spoonfuls of the beaten egg whites to soften the batter.

Gently fold in the remaining egg whites, being careful not to deflate the batter, until you have a smooth, lump-free mixture.

Line a 10-inch (26 cm) cake pan with parchment paper and pour in the batter. Bake for 40 minutes.

Fill a piping bag with the cooled chocolate glaze and cut a very small tip so a thin stream comes out.