Preheat the oven to 170°C.
Mix eggs: Place the 6 egg yolks in a mixing bowl. Add the sugar. Beat the sugar and eggs until pale.
Mix ingredients: Add the flour and baking powder, as well as the softened but not melted butter. Mix everything together.
Prepare DoughPlace the dough in a buttered baking pan (Tefal). Smooth the top with a spoon.
Glaze CakeSpread egg yolk on the cake with a brush and make lines with a fork.
Bake CakeBake for 30 minutes in a low oven.
