I’ve tried several brioche recipes. This one is from Epicurious.
Dough Starter (Sponge):
2 tablespoons water, at room temperature
1 tablespoon sugar
1/4 teaspoon instant yeast
1/2 cup flour
1 cup + 1 1/2 tablespoons flour
2 tablespoons sugar
1 1/4 teaspoons instant yeast
1/2 teaspoon salt
8 tablespoons unsalted butter, very soft
1 large egg yolk
1 teaspoon cream
Begin the night before. In the mixer bowl, place the water, sugar, instant yeast, flour, and egg. Whisk by hand until very smooth, to incorporate air, about 3 minutes. The sponge will be the consistency of a very thick batter. Scrape down the sides of the bowl and set it aside, covered with plastic wrap while you prepare the flour mixture.
In a small bowl, whisk the flour with the sugar and yeast. Then whisk in the salt (this keeps the yeast from coming in contact with the salt, which would kill it). Sprinkle this mixture on top of the sponge. Cover it tightly with plastic wrap and let it stand for 1 1/2 to 2 hours at room temperature. The sponge will bubble through the flour mixture in places.
After the first rise, add the 2 cold eggs and mix with the dough hook on low (#2 if using a KitchenAid) for about 1 minute or until the flour is moistened. Raise the speed to medium (#4 KitchenAid) and beat for 2 minutes. Scrape the sides of the bowl with an oiled spatula and continue beating for about 5 minutes longer or until the dough is smooth and shiny but very soft and sticky. It will mass around the dough hook but not pull away from the bowl completely.
Add the butter by the tablespoon, waiting until each addition is almost completely absorbed before adding the next tablespoon, beating until all the butter is incorporated. The dough will be very soft and elastic and will stick to your fingers. It will firm considerably after chilling.
Using an oiled spatula or dough scraper, scrape the dough into a 1-quart dough rising container or bowl, greased lightly with cooking spray or oil. Lightly spray or oil the top of the dough and cover the container with a lid or plastic wrap. Allow the dough to rise until doubled, 1 1/2 to 2 hours.
Deflate the dough and then place it covered in the refrigerator over night.
In the morning, remove the dough from the refrigerator and gently press it down to deflate it. Cut the dough into 8 pieces and roll them into balls. Place them in a greased loaf pan and let them rise for another hour or so while you preheat the oven to 350 degrees F.
Lightly beat together the egg yolk and cream for the glaze. Brush the top of the brioche with the egg glaze, being careful not to drip any on the side of the pans, or it will impede rising.
Bake for approximately 30-35 minutes. Let cool for 10 minutes and then remove from pan. Best served warm or toasted.