Activating and Mixing the Dough
In a small bowl, whisk the instant yeast into the lukewarm milk. In a large bowl or stand mixer fitted with the paddle attachment, cream the softened butter, granulated sugar, and salt together until smooth. Add the egg and mix until combined. Pour in the milk-yeast mixture, then add the flour in two batches. Mix until a soft, cohesive dough forms.
Creaming the butter prevents the fat from separating, ensuring the dough remains pliable rather than greasy. The lukewarm milk activates the yeast without killing it.
The dough should be smooth, slightly tacky, but hold its shape in a ball without sticking excessively to your hands.