- 2 tablespoons butter or neutral-flavored oil
- 1 large sweet onion, peeled and finely minced
- 1 1/2 pounds grass-fed, extra-lean ground beef
- 1 tablespoon Worcestershire sauce
- 1 teaspoon salt
- Freshly ground black pepper
- 6 slices Gouda or cheddar cheese
- 6 burger buns or ciabatta rolls
- Tomato slices
- Your favorite condiments
In a sauté pan, heat butter or oil over medium heat and add onions. Cook, stirring occasionally, until onions are deep golden brown, about 15 minutes. Cool onions completely. (You can do this step up to a day in advance.)
Combine ground beef with caramelized onions, Worcestershire, salt and pepper, and divide the mixture into 6 portions. Roll each portion into a ball and flatten out to about 3/4-inch-thick.
Cook burgers on a preheated gas or charcoal grill for 6 to 8 minutes to a side, or until a thermometer inserted in the center of the meat reads 155° F. Place a slice of cheese on top of each burger during the last minute of cooking. Remove from the grill and layer onto buns with lettuce, tomato and your favorite burger condiments.