Preparation:
Sprinkle tenderloin with 1/2 teaspoon salt and 1/2 teaspoon pepper. Secure with string at 1-inch intervals. Brown tenderloin on all sides in hot oil in a heavy roasting pan or ovenproof Dutch oven. Remove tenderloin, reserving drippings in pan.
Add butter to drippings and cook over medium-high heat until melted. Add yellow and purple onion rings, and saute 5 minutes.
Add green onions, shallot, and garlic; and saute 10 minutes. Stir in cognac and broth; cook over high heat, stirring constantly, until liquid evaporates (about 5 minutes). Place tenderloin on top.
Bake, covered, at 400 degrees for 45 minutes or until a meat thermometer inserted into thickest portion of tenderloin registers 145 degrees (medium rare).
Remove tenderloin from roasting pan, reserving onion mixture in pan; cover tenderloin loosely, and let stand at room temperature 10 minutes.
Cook onion mixture over medium heat, stirring constantly, 3 to 5 minutes or until liquid evaporates. Stir in remaining 1 teaspoon salt and remaining 1/2 teaspoon pepper. Serve with sliced tenderloin. |