Roast Lamb Loin in a Cage with Rosemary Sauce

To prepare the lamb: Cut the rack in half. Remove the fat and silverskin. Remove four bones from each rack, leaving all the meat attached to the largest end bone. Season the racks with pepper. Heat the olive oil in a large skillet and sear the racks on both sides until browned, 2 minutes per side. Remove from heat and set aside to rest.

Cut the veal into 1-inch pieces and put in a food processor. Season with two pinches of salt and a few grindings of pepper. Add the whole egg and cream. Process until almost smooth. In a medium skillet, heat 1 tablespoon of oil over medium-high heat and add the shallots and mushrooms. Season with salt and pepper. Reduce the heat to medium and saute for 1 to 2 minutes, until softened and translucent but not browned. Take off the heat and cool for 1 minute, then add to the veal in the processor. Pulse twice to blend.

Bring a pan of water to a boil and drop in the pepper strips. Cook 20 seconds, then pour through a sieve or colander to drain off the hot water. Plunge the pepper strips into ice water to set the color. When cool, blot dry.

Lay the puff pastry sheet on a work surface and cut into a lattice by making one row of 1-1/2-inch-long cuts parallel to the long edge, 1-1/2 inches apart. Make a second row of cuts, 1/2-inch away from the first and beginning the cuts 1-1/2 inches above the start of the first cuts, next to the solid section of the first line. Continue making lines of offset parallel cuts across the entire sheet. Cut the sliced sheet in half crosswise to make 2 latticed sheets. The lattice will open as you wrap the lamb.

Preheat the oven to 400 F. Place the lamb racks on a baking sheet and spread with the veal mixture. Cover the lamb with the pepper strips, alternating colors. Wrap each rack in a lattice sheet of puff pastry, letting the lattice open. Turn over, overlap the ends of the lattice, and press to seal. Turn back over so that the seal is at the bottom. The peppers should show through the lattice. Whisk 1 tablespoon of water into the egg yolk and brush the lattices with this egg wash. Bake 10 minutes, or until the lattice “cages” are golden brown.

To make the sauce: Put the stock and 12 rosemary sprigs in a medium saucepan over medium-low heat. Simmer 10 minutes, swirling occasionally to blend. Remove from heat and strain through a fine-meshed sieve. Reserve the two remaining rosemary sprigs.

To make the garnishes: Using the tip of a sharp knife, flute the mushroom caps by drawing the knife point from the center outward to the edge in a spiral, removing a small strip. Repeat until the entire cap is fluted. Bring a saucepan of water to a boil and drop in the tomato quarters and mushroom caps. Boil 5 seconds, then remove with a slotted spoon and plunge into ice water to cool. Rub the mushroom caps with the lemon juice. Pull the skin off the tomato quarters.

To serve: Pool rosemary sauce on each plate. Place a lattice-wrapped lamb piece on each plate and garnish each with two tomato quarters and a mushroom. Stand one of the reserved rosemary sprigs in each mushroom.