1. Gently heat the milk, water and butter in a pan. Crumble the yeast and dissolve it in the milk.
2. Whisk the sugar, salt and eggs together and add to the yeast milk.
3. Add the flour to the mixing bowl, then the yeast milk and knead well until smooth for about 3 minutes using a dough hook. Leave to prove in a warm place for about 30 minutes until it doubles in volume.
4. Divide the dough into 14 portions and shape into balls. Take two balls, shape 6 small balls out of each one and then place them onto the other 12 dough balls.
5. Place the dough balls into a greased muffin tray, cover and leave to prove for about 20 minutes.
6. Pre-heat the oven (fan 150 °C / top and bottom heat 175 °C). Place a fire-proof bowl with water into the oven – this will make the brioches particularly soft.
7. Whisk the egg yolk with some milk, brush the dough balls and then bake for about 12 minutes until the brioches are golden brown.