Roast Pork Tenderloin with Prunes

Combine prunes and Madeira in a saucepan; bring to a simmer. Remove from the heat; cover and set aside. Let the prunes plump for at least 1 hour. Drain, reserving the prunes and Madeira separately.

Lay one of the tenderloins on a large cutting board. Steadying the meat with one hand, place a slicing knife along a long side of the meat. Keep the blade parallel to the board and cut through the meat, stopping short of the opposite edge so that the flaps remain attached. Repeat with the remaining 3 tenderloins.

Working with one tenderloin at a time, open up the flaps as you would open a book. Cover with plastic wrap. With a meat pounder, rolling pin or heavy pan, pound the meat to an even thickness of about 3/8 inch. Repeat with the remaining tenderloins. Discard the plastic wrap.

Overlap 2 sheets of plastic wrap on a work surface to make a large rectangle. Set 2 of the flattened tenderloins on the plastic wrap, slightly overlapping them along a long edge, to form a rectangle approximately 8-by-13 inches. Leaving a 1-inch border at each end, place 10 of the prunes, in a row just to one side of the overlap. Beginning with a long edge, roll the meat as you would a jelly roll, using the plastic wrap to assist and lift in the rolling. Tuck in the ends as best you can, and use butcher's twine to secure the roll with crosswise ties at 1-inch intervals. Repeat these steps with the remaining tenderloins.

Preheat oven to 425 degrees F.

Heat 1 teaspoon oil in a large nonstick skillet over medium-high heat. Add one of the tenderloin roasts and brown on all sides, 5 to 7 minutes. Transfer to a large rack set over a baking sheet. Heat 1 teaspoon of the oil to the pan, brown the second roast and transfer it to the rack. (Do not wash the pan--you will need it later to prepare the sauce.)

Roast the pork until a meat thermometer inserted into the center registers 150 degrees F, 30 to 40 minutes. Transfer to a cutting board, tent with foil and let rest for 10 minutes.

While the pork is roasting, chop the remaining 4 prunes. Add the remaining 1 teaspoon oil to the pan used to brown the meat and heat over medium-high heat. Add shallots and the chopped prunes; cook, stirring, until the shallots are soft, 1 to 2 minutes. Pour in the Madeira left from soaking the prunes and bring to a boil, stirring to loosen any browned bits clinging to the bottom of the pan. Boil until almost all the liquid has evaporated, 3 to 4 minutes. Pour in broth and boil until the sauce has reduced to 2 cups, about 10 minutes. Strain the sauce through a sieve into another saucepan. Bring the sauce to a simmer.

Stir together cornstarch and water in a small bowl. Whisk into the sauce and cook, whisking, until slightly thickened. Season with salt and pepper.

Remove the twine from the roast tenderloins and carve into 1/2-inch-thick slices. Arrange on a heated platter and serve with the sauce.