Preheat the oven to 375 degrees F (190 degrees C). Line a sheet pan with a piece of parchment paper and place an oven-safe wire rack over the parchment paper. Set aside.
In a large skillet, heat the Olive Oil (1 tablespoon) over medium high heat. Add the Pancetta (2 ounce) and cook until it has rendered some fat and started to crisp. Use a slotted spoon to transfer the pancetta to a small bowl.
Add the Onion (1 cup), Celery (1 stalk), and Apple (1 cup) to the pan and cook, stirring occasionally, until the vegetables and apple become slightly translucent and tender.
Stir in the Fresh Sage (2 teaspoon), Fresh Rosemary (1 teaspoon), and Ground Black Pepper (1/4 teaspoon) and cook for an additional minute until fragrant.
Remove from heat and add the Bread (4 cup) and pancetta and toss to coat. Drizzle Low-Sodium Chicken Broth (1/2 cup) over the bread and stir well to mix. If the bread still seems dry, add more broth 1 to 2 tablespoons at a time. Sprinkle Parmigiano-Reggiano (1/2 cup).
Lay a piece of parchment paper on a flat, solid surface and one at a time, place one Turkey Tenderloin (2) in the center. Place another piece of parchment on top of the tenderloin.
Use the flat side of a meat mallet to pound the tenderloin down to about 1/4 to 1/3 inch thick, flipping halfway through pounding. Be careful not to tear the flesh. Set aside and continue with the second tenderloin. Set aside.
Lay 4 slices of Prosciutto di Parma (8 slice) lengthwise, side by side and slightly overlapping. Lay one tenderloin on top of the prosciutto. Fill the center of the tenderloin with stuffing and turkey around the stuffing, like a jelly roll.
Use kitchen string to secure the roll in the middle and at each end. Place the turkey rolls on the wire rack and roast for 30 to 35 minutes or until turkey is cooked to 160 degrees F.
If there is leftover stuffing, spray an ovenproof ramekin with vegetable spray and put the rest of the stuffing in the dish. Dot with Butter (1 tablespoon) cut into very small pieces and bake for 10-15 minutes with the turkey.
While the turkey is cooking, make the gravy. Melt the remaining butter in a small saucepan over medium-high heat and add the Sage Leaves (1). Cook for about a minute, then add the All-Purpose Flour (1 tablespoon) and whisk, cooking for about a minute.
Add the White Wine (1/4 cup), whisking constantly and cook for 30 to 45 seconds, then whisk in the Chicken Broth (3/4 cup). Continue stirring and cooking until mixture comes to a boil. Reduce heat to a light bubble and continue to cook for 1 minute.
Add the Heavy Cream (1 tablespoon) and Maple Syrup (2 teaspoon). Remove from heat and season with Salt and Pepper (to taste).
Remove from oven and let the turkey rest for 5 minutes before carving. Slice the turkey roll in one inch wide slices. Serve with gravy and extra stuffing.