Homemade Chocolate Croissants

(4 Tablespoons; 60g) unsalted butter, softened to room temperature

all-purpose flour, plus more for rolling/shaping

granulated sugar

salt

active dry or instant yeast

and 1/2 cups (360ml) cold whole milk

bar (113g) semi-sweet or bittersweet chocolate, coarsely chopped

optional: confectioners' sugar for dusting

and 1/2 cups (3 sticks; 345g) unsalted butter, softened to room temperature

all-purpose flour

large egg

whole milk