For Brioche Dough – bread flour – sourdough starter – milk
To make the dough, combine your sugar, milk, salt, eggs, butter, and the bubbly sourdough starter in a mixing bowl of a stand mixer.
For bulk fermentation, transfer the dough to a lightly oiled bowl, cover it with plastic wrap or a damp towel, and let it rest in a warm spot. After bulk fermentation is done, transfer the dough into the fridge.
Turn the dough onto a floured work surface and divide it into 16 equal pieces. The easiest way to do this is with a dough scraper, but a sharp knife works too.
For the second rise, place the dough balls in parchment paper-lined loaf pans or coat your loaf pan with butter or oil.