Heat oven to 325 degrees. Season ribs with salt and pepper. Heat nonstick skillet over medium-high heat. Working in batches, brown ribs 7-10 minutes. Put in large, deep ovenproof pot. Drain fat from skillet and heat oil over medium-high. Add leeks and sauté until browned, about 8 minutes. Add 2 cups mango nectar, tequila, broth and chipotle, simmer 1 minute. Pour over ribs. Bake, uncovered, in 325 degree oven for 3 hours or until the ribs are very tender, turning every 45 minutes. Remove pot from oven. Let ribs cool in sauce, uncovered, 30 minutes. Remove ribs from sauce and refrigerate, covered, overnight. To serve, discard fat from sauce. Add remaining 3 tablespoons nectar and ribs to sauce. Reheat over medium heat, 20 minutes. Top with scallion.
Makes 12 servings