Ingredients
- 2 pounds ground beef
- 2 tablespoons Worcestershire sauce
- ½ teaspoons garlic powder
- ½ cup butter divided
- 1 extra-large sweet onions peeled and sliced into thin strips
- 12 slices thick-cut sandwich bread Texas toast
- 6 slices American cheese
- 6 slices Swiss cheese
- 2 tablespoon yellow mustard
- Salt and pepper
