Put the fresh yeast and milk in the stand mixer bowl, cover with flour, knead for 7–8 minutes on low speed, then add the cold butter and knead again for 8 minutes.

Rest the dough for 2 hours.

Meanwhile, form the butter into a roughly 20 cm square, add the sugar in the centre, close and seal it well, then chill the square in the refrigerator.

After 2 hours, roll out the dough, place the sugared butter square in the centre, and enclose it in the dough, sealing it well.

Roll out the dough, then fold the top toward the centre and the bottom over the top to make a single turn.

Repeat this operation twice, roll out the dough again, form roughly 16 × 16 cm rectangles, fold them toward the centre twice, then place them in buttered and sugared moulds.

Bake for 25 minutes at 180°C, extending the baking if it is not cooked enough.