Prepare the butter by bringing it to room temperature. Line the baking mold with parchment paper. Preheat the oven to 150°C. Cut the candied chestnuts into 5–6 pieces each.

Crack the eggs into a bowl and mix them.

In a separate bowl, cream the butter until it becomes pale. Gradually add the eggs, mixing well after each addition.

Gradually add the sweet sake to the butter mixture, mixing until fully incorporated.

Sift the dry ingredients (cake flour, salt, baking powder) into the mixture. Fold gently with a spatula until no dry spots remain. Add 4 candied chestnuts and mix lightly.