Mix the dough: In a stand mixer with a dough hook combine flour, cold eggs, cold milk, sugar, salt, and instant yeast. Mix on low until everything comes together into a shaggy dough then increase to medium speed and knead for a few minutes until the dough starts to smooth out.
Add the butter: With the mixer running on medium speed add the cold butter a few cubes at a time waiting for each addition to incorporate before adding the next. Continue kneading until the butter is fully incorporated and the dough is smooth, elastic, and passes the windowpane test.
First rise: Shape into a smooth ball, cover, and let rise at room temperature until doubled in size.