This makes a great patio supper and is perfect for a party. The salsa is best in the summer, made with flavourful garden-fresh tomatoes. If using a Premium Rotisserie Roast such as Prime Rib, reduce the marinating time to 2 to 4 hours, just long enough to develop flavour.
Combine onion, oil, lime juice, brown sugar, garlic, allspice, thyme, hot pepper sauce, cinnamon, nutmeg, salt, pepper and chilli flakes in large sealable freezer bag. Remove 2 tbsp (30 mL) of the marinade and set aside to use in salsa. (For spicier salsa, reserve 3 tbsp/45 mL) Pierce roast all over with fork and add to bag; seal and refrigerate for 12 to 24 hours. Discard marinade and pat roast dry.
Place drip pan under grill; add 1/2 inch (1 cm) water to pan. Preheat barbecue to medium-high (400°F/200°C). Cooking with rotisserie: Insert spit rod lengthwise through centre of roast; secure with holding forks and place over drip pan. Cooking without rotisserie: Place roast on grill over drip pan that is moved to one side; turn off heat under roast.
Insert meat thermometer into middle of roast, avoiding spit rod (if using). Cook at constant heat in closed barbecue until thermometer reads 155°F (68°C) for medium (about 30 minutes per lb/500 g). Remove roast to cutting board; tent with foil for 10 to 15 minutes. Carve thinly across the grain. Place slices along centre of lightly grilled tortillas. Top with Avocado Salsa.
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.