Coat steaks with 4 tablespoons of the TABASCO® Chipotle Sauce; cover and refrigerate at least 1 hour, or up to 8 hours.
Heat oil in a large nonstick skillet over medium-high heat until hot. Add steaks and sprinkle with salt to taste. Cook 6 to 8 minutes for medium rare, turning once.
Remove steaks from pan; keep warm. Add onion and sugar to pan and cook until onion is nicely caramelized, about 5 minutes. Stir in broth, remaining 2 tablespoons TABASCO® Chipotle Sauce and 1/4 teaspoon salt; scrape any browned bits from bottom of pan and boil until slightly thickened, about 2 minutes.
Serve steaks topped with caramelized onions; garnish with avocado or parsley.
Makes 4 servings.