Ingredients
Caramelized Onion
1 tablespoon Land O Lakes® Butter
2 large (4 cups) yellow onions, sliced
1 teaspoon finely chopped fresh thyme leaves
1 teaspoon white wine vinegar
1
4 teaspoon coarse ground pepper1
8 teaspoon saltBurger
1 1
2 pounds lean ground beef2 tablespoons stone-ground mustard
1
4 teaspoon salt2 teaspoons coarse ground pepper
4 onion hamburger buns