In a large skillet, cook onion in butter over low heat until tender, about 8 minutes. Cool for 10 minutes.
Place in a large mixing bowl. Add milk, sugar, salt, herbs, yeast and 3 cups flour; beat until smooth. Stir in enough remaining flour to form a soft dough.
Turn onto a floured board; knead until smooth and elastic, about 6 to 8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 45 minutes.
Punch the dough down. Shape into a ball and place on a greased baking sheet. Cover and let rise until doubled, about 45 minutes.
Bake at 375° for 25 to 30 minutes. Remove to a wire rack; brush with melted butter. Cool.