Weigh out the ingredients
You'll need flour, salt, milk, sugar, yeast, eggs, vanilla, and butter.
Activate yeast; Mix in eggs & vanilla
In a glass measuring cup, combine the warm milk, sugar, and yeast. Mix the eggs and vanilla into the milk yeast mixture.
In the bowl of a stand mixer fitted with a dough hook attachment, mix the flour and salt together. Pour the wet ingredients into the flour and mix on low-medium speed for about 3 minutes, or until it forms a ball around the hook.
Add wet ingredients to dry
Add in a few pieces of butter at a time, allowing them to fully incorporate before adding more. Once all of the butter is incorporated, turn the mixer up to medium-high speed and mix for 8-12 minutes.
Mix in the butter
To check if the dough is ready, tear off a small piece and carefully spread it out to see if you can see the light through it without it tearing. If it tears, mix for another minute or two and check again.
Perform windowpane test
Once the dough is ready, transfer it to a lightly greased bowl, cover with plastic wrap, and allow to proof overnight in the fridge. Alternatively, you can let the dough rise in a warm place for about 1 hour or until doubled in size.
On a lightly floured surface, divide the proofed dough into eight equal pieces, weighing about 65g each (you'll have a little extra). On a non-floured surface, flatten each piece, then bring the edges over and press into the middle.
Divide the dough
Turn the dough over and roll into a smooth ball. You can bake the extra dough in a small loaf pan, if desired.
Shape the dough
Arrange the dough in a non-greased pullman pan. Brush with an egg wash, then cover and proof at room temp for about 1 hour, or until doubled in size. Brush the dough with the egg wash again, then bake at 400 degrees F for 15 minutes or until evenly golden brown, then turn the oven down to 350 degrees F, and bake for another 30 minutes until deeply golden.
Proof & bake
Enjoy this brioche loaf plain as dinner rolls, sliced as sandwich bread, or turn into french toast!