Add milk, melted butter and sugar to the yeast mixture and give it a good stir (using the paddle attachment). Add 1 cup to 1 1/2 cups of flour to make a medium batter. You’re looking for a pancake-like consistency. Next, add egg and salt and incorporate well. Switch to the dough hook and with the mixer running on medium speed, add remaining flour. Continue mixing for 5 minutes or until dough is smooth.