Basque-style sirloin with roasted peppers

Season the beef, then put on a plate, loosely cover with foil and set aside at room temperature for up to 30 minutes. Meanwhile, heat the grill to high. Cut the tops off the peppers and discard the seeds; arrange in a roasting tin and toss with 1 tbsp oil. Grill for 15-20 minutes, turning occasionally, until well-charred. Transfer to a bowl, cover and set aside to cool. Once cool, peel the peppers (discarding the skins), thinly slice and set aside.

Preheat the oven to 120°C, gas mark ½. Line a large baking tray with foil and set a wire rack on top. Wipe the excess salt off the beef and put on the rack. Roast for 1 hour 15 minutes for mediumrare (cook for 5 minutes less or more depending on your preference). Carefully lift the rack off the tray and set the beef aside.

Heat 2 tbsp oil in a frying pan over a medium heat, then fry the garlic for 2-3 minutes until golden and crisp. Use a slotted spoon to transfer to a plate, then add the cooked peppers, vinegar and sugar to the pan. Season and heat through, return the crispy garlic, then set aside to keep warm. Heat the grill to medium-high.

Return the beef to the tray (without the rack) with the salad onions. Drizzle everything with the remaining 2 tbsp oil, then put under the grill, turning the beef every 2-3 minutes until the top and sides are well-browned (6-9 minutes). Transfer to a board, cover loosely in foil and leave to rest for 20-30 minutes. Continue to grill the salad onions, if necessary, until charred. To serve, cut the bone away from the sirloin, then slice against the grain into 0.5cm-thick slices. Serve alongside the peppers and salad onions, with fries and garlic mayonnaise, if liked.