Activate the yeast: In a small bowl, stir together the warm milk, yeast, and 1 teaspoon sugar. Let sit for 5–10 minutes until foamy and bubbly.

Start the dough: In a large mixing bowl (or stand mixer bowl), combine flour, remaining sugar, and salt. Add the eggs and the foamy yeast mixture. Mix until a sticky dough forms.

Add the butter slowly: With the mixer running on low (or mixing by hand), add softened butter a piece at a time, letting each piece blend in before adding the next. Continue mixing until the dough looks smooth, elastic, and slightly glossy (about 8–12 minutes in a mixer).

First rise: Transfer dough to a lightly greased bowl. Cover with a clean towel and let rise in a warm spot for 1–2 hours, until doubled in size.

Shape the loaf: Gently punch down the dough. Shape into a loaf and place into a greased loaf pan. Cover and let rise again for 45–60 minutes, until puffy and domed.

Egg wash and bake: Preheat oven to 350°F (175°C). Brush the top of the loaf with beaten egg. Bake for 25–30 minutes, until deeply golden and the loaf sounds hollow when tapped. If browning too fast, loosely tent with foil.

Cool and slice: Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing for the softest, fluffiest crumb.