2 medium fennel bulbs—halved, cored and finely chopped, plus 2 tablespoons
minced fennel fronds
1/2 small onion, minced
1 teaspoon finely grated lemon zest
One 4-pound boneless veal loin, tied at 2-inch intervals with kitchen string
Salt and freshly ground pepper
1/2 cup Dijon mustard blended with 1/2 cup crème fraîche
10 sage leaves
1 1/2 teaspoons fennel seeds, lightly toasted and finely ground
In a large saucepan, cover the limas with 4 inches of water and bring to a boil. Simmer over low heat for 1 hour, then add water to cover by 2 inches. Add the garlic, chopped fennel, onion and lemon zest. Boil over moderately high heat for 15 minutes, stirring often. Reduce the heat to low and simmer, stirring occasionally, until the lima beans and fennel become a thick and creamy puree, about 2 hours.
Meanwhile, preheat the oven to 450°. Season the veal roast with salt and pepper and set it, fat side down, on a rack set in a medium roasting pan. Spread half of the mustard cream over the veal and top with half of the sage leaves. Put the roast in the oven, reduce the temperature to 300° and roast for 45 minutes. Carefully turn the veal fat side up; spread with the remaining mustard cream and top with the remaining sage leaves. Roast the veal for 1 hour longer, or until an instant-read thermometer inserted in the thickest part of the meat registers 145°. Transfer the veal roast to a carving board to rest for 10 minutes.
Stir the ground fennel seeds into the fennel-lima puree. Season with salt and pepper. Discard the kitchen string and slice the meat thickly. Transfer the veal to plates and spoon the fennel-lima puree alongside. Garnish with the fennel fronds.
The fennel-lima puree can be refrigerated overnight. Reheat gently.