• 15 g (½ oz) dried yeast
• 4 tablespoons lukewarm water
• 500 g (1 lb) plain flour, or more if needed
• 2 teaspoons salt
• 1 tablespoon caster sugar
• 6 eggs, beaten
• oil for greasing
• 250 g (8 oz) unsalted butter, cut in pieces, plus extra for greasing
• 2 X 500 g (1 lb) saucissons a l’ail aux noisettes (garlic sausages with hazelnuts), poached and chilled
• 1 egg, beaten with ½ teaspoon salt

Sprinkle the yeast over the water in a small bowl and leave it for about 5 minutes until dissolved. Sift the flour into the mixer bowl, adding the salt and sugar. Make a well in the centre and add the eggs and yeast mixture. Work with the dough hook, beating slowly until the ingredients are mixed and then work at top speed for about 5 minutes. If you are kneading by hand, do so for 8–10 minutes. Add more flour if necessary so the dough is soft but not sticky. When sufficiently kneaded the dough will have the colour and texture of chamois leather.

Shape the dough into a ball, put it in an oiled bowl and turn it so the top is oiled. Cover it with a wet cloth and leave in a warm place for 1½-2 hours to rise until it has doubled in bulk. Work the dough lightly with your hands to knock out the air and then knead in the pieces of butter. Continue working in the mixer until all the butter is incorporated and the dough is smooth. Shape the dough into a ball again, oil it and cover it with a wet cloth. Keep it in the refrigerator for 6 hours or overnight: chilling makes it much easier to shape.

Butter two 1 kg (2 lb) loaf tins. Divide the dough in half and roll each piece to an 18 X 30 cm (7 X 12 inch) rectangle. Peel the sausages and set one lengthways on each piece of dough. Wrap the dough around the sausages and pinch the edges to seal them. Set the rolls, seam-side down, in the tins. Brush the tops with beaten egg glaze; be careful not to let any glaze run down the sides or the loaves will stick to the tins. Cover with a damp cloth and leave the brioches to rise in a warm place until the tins are full, about an hour. Preheat the oven.

Brush the loaves again with glaze and score them with a lattice with the point of a knife, or snip ‘hedgehog points’ with scissors. Bake in the oven for 40–45 minutes until the brioches are well browned and start to shrink from the sides of the tins. Turn the loaves out on a rack to cool. For serving, cut them in thick slices, discarding the ends. Sausage in brioche is best eaten on the day you make it, but it can be kept in the refrigerator for a day or two.