In a large skillet, cook onion in butter over medium heat for 15-20 minutes or until onion is golden brown, stirring frequently. Stir in wine or broth and garlic. Bring to a boil. Reduce heat; simmer, uncovered, for 3-4 minutes or until liquid has evaporated.
Meanwhile, combine the rosemary, salt and pepper; rub over steaks. Broil 4 in. from the heat for 7-9 minutes on each side or until meat reaches desired doneness (for medium-rare, a meat thermometer should read 145 degrees F; medium, 160 degrees F; well-done, 170 degrees F). Serve with caramelized onions.
1 large onion, halved and sliced
2 tablespoons butter or margarine
1/3 cup white wine or chicken broth
1 garlic clove, minced
1/2 teaspoon dried rosemary, crushed
1/4 teaspoon salt
1/4 teaspoon pepper
2 beef tenderloin steaks,
1 1/2 to 2 inches thick