1 tablespoon butter
1 small red onion, diced
1 tablespoon minced garlic
3/4 cup plain lowfat yogurt
1 teaspoon salt
1 teaspoon black pepper
1 teaspoon cayenne pepper
1 teaspoon mustard powder
1 teaspoon garlic powder
1 tablespoon horseradish
1 tablespoon chopped fresh parsley
1 tablespoon chopped fresh cilantro
2 tablespoons Worcestershire sauce
2 tablespoons low-sodium soy sauce
1 tablespoon chipotle-flavored hot sauce
2 pounds lean ground beef