Sprinkle dry yeast over warm water in a large bowl, stir until dissolved, and let foam for 10 minutes.
Stir sugar, 1/4 cup softened butter, and salt into hot milk until dissolved, then cool to 105°F–115°F.
Combine cooled milk mixture with the foamed yeast, then blend in the beaten egg.
Beat in 4 cups of sifted flour, 1 cup at a time, to form a soft, workable dough.
Turn dough onto a floured pastry cloth and knead lightly for 5 minutes using remaining flour on hands.
Place dough in a warm, buttered bowl, turn greased side up, cover, and let rise 1.25 to 1.5 hours until doubled.
Punch dough down and knead 4 to 5 minutes on your floured cloth, keeping dough slightly sticky.
Cut dough into 16 equal pieces, roll into smooth 1 3/4-inch balls, pulling sides down and under.
Place rolls bottom side down in a well-buttered 13x9x2 inch pan in neat rows.
Cover and let rise in a warm place for 30 to 45 minutes until doubled in bulk.
Brush tops with melted butter and bake at 375°F for 18 to 20 minutes until nicely browned.
Remove from oven and immediately brush with extra melted butter for a perfectly soft, sizzling crust.