Mix the Dry Ingredients: In a large bowl, combine the bread flour, salt, and sugar. Ensure the ingredients are evenly distributed. This step sets the foundation for a uniform brioche dough.
Activate the Yeast: In a small bowl, dissolve the active dry yeast in 50 ml of the whole milk. Allow the mixture to sit for about 5 minutes until you see a slight froth. If using instant yeast, you can mix it directly with the flour.
Combine Wet Ingredients: In another bowl, beat the eggs and mix them with the remaining whole milk. Add the softened unsalted butter to this mixture. Stir until you get a smooth, combined liquid.
Mix the Dough: Using a stand mixer fitted with a dough hook, slowly pour the wet ingredients into the bowl of dry ingredients. Add the yeast mixture. Start mixing on low speed to avoid splashing. Increase the speed gradually until the dough comes together as an enriched dough. The dough should be soft and slightly sticky. If needed, add a tablespoon of water to help make brioche dough if it feels too dry.
Knead the Dough: Knead the dough for about 10 minutes in the mixer or by hand on a lightly floured surface. The goal is to develop the gluten, so the dough will be easier to shape later. The dough will be slightly sticky but should pull away from the sides of the bowl.