Directions

1. Preheat the oven to 350°F. Place the apple pieces in an oven-proof casserole dish. Add the carrots and new potatoes (if using), toss with a bit of oil and season generously with salt and freshly ground pepper. Set aside.
2. Butterfly the tenderloin. Lay the tenderloin down on the cutting board and make a cut down the length of the tenderloin with your knife parallel to the cutting board; do not cut all the way through. Open the loin like a book (or think of it like unrolling a carpet). Continue to cut through the thicker part of the roast, keeping 1/2 an inch from the bottom of the meat, cutting and unrolling to lay flat. If uneven, use a meat pounder to pound to an even thickness.
3. Sprinkle the loin with the rosemary, fennel and apple. Season with salt and freshly ground pepper. Tightly roll and tie with twine at 1-2-inch intervals until the entire tenderloin is tied up.