How to Make It
Preheat the oven to 450°. In a large roasting pan, toss the ribs with the oil, fennel and crushed red pepper and season with salt and pepper. Spread the ribs in an even layer and roast for about 20 minutes, until cooked through.
Meanwhile, in a small saucepan, warm the marmalade over moderate heat until it becomes pourable, about 1 minute.
Turn the broiler on. In a very large bowl, toss the ribs with the marmalade until well coated. Return the ribs to the roasting pan meat side up and scrape any marmalade left in the bowl over the ribs. Broil the ribs 6 inches from the heat for about 3 minutes, basting twice with the juices, until golden all over and charred in spots. Sprinkle the ribs with the rosemary and transfer to plates. Spoon any juices from the roasting pan over the ribs and serve.