Heat milk in a saucepan over medium heat until just bubbling. Remove from heat and mix with sugar and 4 tablespoons butter. Let cool to 110-120°F (43-48°C), then stir in yeast and let stand until foamy.

In a stand mixer bowl, combine the milk mixture, salt, egg yolk, 1 egg, and half the flour. Mix on low speed, then gradually add remaining flour and mix until dough comes together. Beat at medium speed until dough is smooth and elastic.

Transfer dough to a greased bowl, cover, and let rise in a warm place until doubled in size.

Roll dough into a 16x8-inch rectangle and fold in half to form a 16x4-inch rectangle. Cut into 16 2-inch squares and arrange on a parchment-lined sheet. Cover and let rise until doubled.

Preheat oven to 350°F (175°C). Brush rolls with egg wash and bake until golden brown, 12-16 minutes.