- With the rack in the middle position, preheat the oven to 500°F (260°C).
- Place the vegetables and the oil in the centre of a large double-layer sheet of foil. Season with salt and pepper. Close the papillote tightly. Set aside.
- In a bowl, combine the blue cheese (if using), walnuts, parsley and chives. Refrigerate until ready to serve.
- In a bowl, combine the flour, pepper, salt, onion powder, garlic powder and nutmeg.
- On a baking sheet lined with foil, rub the roast with the spice mixture on all sides. Arrange the roast fat side up on the baking sheet. Roast for 45 minutes along with the vegetable papillote. After 45 minutes, turn the oven off and keep the door closed for 2 hours. At this stage, it is very important to prevent any heat from escaping the oven.
Madeira Green Peppercorn Sauce
- Meanwhile, in a large skillet over medium-high heat, melt the butter. Add the flour and garlic. Continue cooking, stirring constantly, for 5 minutes or until golden.
- Add the broth, Madeira, green peppercorns and black pepper. Bring to a boil, whisking constantly. Reduce over medium heat until the sauce coats the back of a spoon. Keep warm.
- Remove the vegetables and the roast from the oven. Run the blade of a chef’s knife between the meat and the bone. Cut the meat into thin slices.
- Spread the blue cheese topping over the vegetables. Serve with the roast and the sauce.