With the rack in the middle position, preheat the oven to 180 °C (350 °F). In a bowl, combine spices, salt and Cayenne pepper. Coat roast with spice mixture.
In a large ovenproof skillet, brown the onions in the oil. Season with salt and pepper. Place the meat in a roasting pan and roast for about 1 hour or until a thermometer inserted in the centre of the roast reads 135 °F (57 °C). Transfer the roast to a platter, cover with aluminium foil and let rest until the thermometer reads 145 °F (63 °C). Keep the onions warm.
Warm Bacon Dressing
In a small saucepan, brown the bacon in the oil until crisp. Add the shallot and cook for about 1 minute. Deglaze with the vinegar and whiskey. Add the parsley. Season with salt and pepper. Serve the meat with the onions, warm dressing, sweet peas and Mashed Rutabaga and Carrots (see recipe).
If you don’t have whisky, replace it with additionnal 15 ml (1 tablespoon) of vinegar.