- In a food processor, finely chop the leek and carrot. Transfer to a bowl. Chop the mushrooms and set aside separately.
- In a large skillet over high heat, soften the leek and carrot in the butter. Add the mushrooms and cook for 5 minutes or until the mixture begins to brown. Add the meat and continue cooking, breaking up the meat with a wooden spoon. Add the remaining ingredients. Bring to a boil and simmer over medium-low heat for 8 to 10 minutes or until almost dry. Season with salt and pepper. Refrigerate the mixture for 2 hours or until completely chilled.
- With the rack in the lowest position, preheat the oven to 375°F (190°C).
- On a work surface, open the turkey roast flat, skin side down. Season with salt and pepper. Spread the stuffing mixture in the centre. Close the roast. Place the butcher’s twine under the roast so that the ends extend out on each side. Close and tie the roast, cutting off any excess twine.
- In a large oven-safe skillet over high heat, brown the roast on all sides in the butter. Season with salt and pepper.
- Bake for 1 hour and 30 minutes or until a meat thermometer inserted into the centre of the stuffing reads 165°F (74°C). If needed during cooking, add water to the skillet to prevent burning the pan juices. Reserve the pan juices for the sauce. Let the roast rest while preparing the sauce.
- Meanwhile, in a large skillet over high heat, brown the mushrooms and shallots in the butter.
- Deglaze with the white wine and reduce by half. Add the broth, toasted flour and nutmeg. Bring to a boil, stirring constantly. Let simmer over high heat for 30 minutes or until the sauce has reduced by half. Add the reserved pan juices. Season with salt and pepper.