Texas-spiced prime rib of beef

Method

1. To make the spice rub, put a heavy-based frying pan over a medium heat. Add the cumin, coriander and yellow mustard seeds, the chilli flakes and black peppercorns, then toast for 2-4 minutes until fragrant. Don’t overdo it or the spices will be bitter. As soon as you can hear and see the mustard seeds starting to pop, take the pan off the heat. Transfer the spices to a bowl to cool.
2. Grind the toasted spices and celery seeds in a pestle and mortar or spice mill, then stir in the garlic powder, sugar and salt. (The rub will keep in an airtight container, away from heat, for up to 1 month.)
3. Use roughly 1 tbsp rub for every 500g meat. Rub the spice mix all over the meat, then leave overnight in the fridge, wrapped in cling film or in a sealable plastic bag. This will add depth of flavour and also form a good crust on the meat (known in barbecue circles as bark).
4. When ready to begin, set up the barbecue for indirect cooking. When the coals are ready, scatter half the wood chips on to them.
5. Put the beef rib on the rack, fat-side up, over the drip pan, away from the direct heat, then cover the barbecue with the lid. Adjust the vents – closed will extinguish the fire and fully open might make it too hot.
6. Barbecue the beef for a minimum of 2-2½ hours, trying to keep the temperature inside the lid around 160-180°C. (If your barbecue doesn’t have a temperature gauge, insert a thermometer through the top vents now and then.) The beef is ready when a thermometer pushed into its centre reads 50°C for rare, 55-60°C for medium rare, 60-70°C for well done. To maintain the heat, add about 12 new coals per side every hour. Toss the rest of the wood chips on the coals after the first hour of grilling, but open the lid as little as possible while the meat is cooking.
7. Once cooked to your liking, remove the meat from the barbecue and rest it, covered with foil, for 15 minutes. Carve the meat, then serve.