1. Warm the milk. Crumble the fresh yeast into the milk.
2. In the bowl of a food processor pour the flour, egg, salt and sugar. Add the milk and knead the dough. Add the butter last. Continue to knead until the dough comes off the sides of the bowl (add a little flour if necessary).
3. Cover the bowl with a damp cloth and let rise for 45 minutes in a warm place.
4. Degas and shape the brioche in its mold, or in a braid.
5. (Optional) If the brioche is molded, cover the pan with a damp cloth and let rise in a warm place for another 45-60 minutes (avoid cracking in the brioche during baking).
6. Brush with milk. Bake in a preheated oven at 160 ° for 40 minutes.