For the stuffing:
• 3 slices whole-wheat sandwich bread (about 4 ounces), torn into rough 1-inch pieces
• 1 medium fennel bulb (about 8 ounces), stalks removed, cored, and cut into 1-inch pieces
• 1/2 medium Granny Smith apple, cored and cut into 1-inch pieces
• 1/2 medium yellow onion, cut into 1-inch pieces
• 4 tablespoons unsalted butter (1/2 stick)
• 2 teaspoons finely chopped fresh rosemary leaves
• Kosher salt
• Freshly ground black pepper
For the pork:
• 1 tablespoon plus 1 teaspoon kosher salt
• 1 tablespoon fennel seeds, lightly crushed using the bottom of a frying pan
• 1 tablespoon finely chopped fresh rosemary leaves
• 1 teaspoon freshly ground black pepper
• 1 teaspoon packed dark brown sugar
• 1 (4- to 4-1/2-pound) boneless pork loin (NOT a tenderloin)
• 3 ounces thinly sliced prosciutto
• 1 tablespoon olive oil
For the stuffing:
1. Place the bread in a food processor fitted with a blade attachment and pulse into fine crumbs, about 15 (1-second) pulses. Remove to a large bowl and set aside.
2. Place the fennel, apple, and onion in the food processor and pulse into fine pieces no larger than a grain of rice, scraping down the sides of the bowl as needed, about 20 (1-second) pulses; set aside.
3. Melt the butter in a large frying pan over medium heat. Add the processed fennel mixture and the rosemary, season with salt and pepper, and cook, stirring occasionally, until the vegetables are softened, about 15 minutes.
4. Remove the mixture to the bowl with the breadcrumbs and stir until combined and the bread is evenly moistened. Taste and season with salt and pepper as needed; set aside to cool for at least 15 minutes. Meanwhile, line a rimmed baking sheet with foil and cut 6 (18-inch) lengths of kitchen twine; set the baking sheet and twine aside.
For the pork:
1. Mix the salt, fennel seeds, rosemary, pepper, and sugar in a small bowl until combined; set aside.
2. To butterfly the pork, place it on a cutting board with one end pointing toward you. Slice lengthwise down the center, almost but not quite cutting through the pork, leaving about 1/2- to 3/4-inch thickness of meat intact.
3.Open the pork up like a book and push on it to flatten.
4. Starting on the left side, with the blade of the knife parallel to the cutting board and the blade facing left, slice down the length of the seam, maintaining the 1/2- to 3/4-inch thickness
5. Pull the meat open and press down to flatten. Continue cutting and flattening until the entire left half is 1/2- to 3/4-inch thickness. Rotate the pork and repeat on the other half.
6. Evenly spread the reserved stuffing over the pork, leaving a 1-1/2- inch border
7. Horizontally arrange the prosciutto over the stuffing, one piece slightly overlapping the next.
8. Starting on the right side, roll the pork into a tight cylinder.
9. Tie the pieces of twine around the pork, spacing them about 1 1/2 inches apart and trimming off any excess.
10. Using your hands, rub the oil evenly over the outside of the pork, then rub the the. roast with all of the reserved spice mixture.
11. Place the roast seam-side down on the prepared baking sheet and let it sit at room temperature for 30 minutes. Meanwhile, heat the oven to 450°F and arrange a rack in the middle.
12. Roast until the pork is light golden brown on top, about 30 minutes. Reduce the oven temperature to 375°F, rotate the baking sheet, and roast until an instant-read thermometer inserted into the center of the pork registers 145°F, about 25 to 35 minutes more. Let the roast rest on the baking sheet loosely tented with foil for 20 minutes before slicing.
This may seem like a lot of work, because it is. BUT it is so very delicious and has become our favorite Christmas Day entree. It's one of the few recipes where I didn't change a thing!
Hints: Only use fresh breadcrumbs. You can make the stuffing and fennel rub a day ahead, then butterfly, stuff and roast the next day. Watch that you change the oven temperatures as indicated. Also, roasting to 140 should be enough, just be sure to let it rest. Pork can be a little pink!
Check for videos on how to butterfly the roast if you're not sure of the process.
(adapted from CHOW)