In a mixing bowl, combine flour, sugar, salt, and yeast.
Add warmed milk and melted butter to the dry ingredients. Mix until a dough forms.
Knead the dough on a floured surface for about 10 minutes, until smooth and elastic.
Place the dough in a greased bowl, cover, and let rise in a warm place for about 1 hour, or until doubled in size.
Punch down the dough and roll it out to about ½ inch thickness. Cut out rounds using a biscuit cutter or a glass.
Dust a baking sheet with cornmeal and place the dough rounds on it. Cover and let rise for another 30 minutes.
Preheat a griddle over medium heat. Cook the muffins for about 7-10 minutes on each side, until golden brown and cooked through.
Cool on a wire rack before serving.