• In large pot, combine lamb shanks with broth, chili powder and 1 onion, sliced. Cover; bring to a boil. Simmer 2 hours or until lamb is tender.
• Remove shanks from broth and when cool enough to handle, pull meat off bones into shredded pieces.
• Slice remaining onion; gently sauté in oil over medium heat until sweet and caramelized.
• Spread bread with goat cheese. Stack 4 slices with arugula, tomatoes, shredded lamb and caramelized onions. Close sandwiches. If preferred, stack all ingredients on tortillas.