Nan's Chargrilled Sirloin Steak & Avocado-Rocket Salad

While the potato is cooking, thinly slice the tomato into wedges. Thinly slice the red onion. Zest the lemon to get a pinch, then slice in half. Finely chop the garlic. In a medium bowl, combine Nan's special seasoning and a drizzle of olive oil. Add the sirloin steak and toss to coat.

When the BBQ is hot, add the lemon, cut side down, and grill until charred, 4-6 minutes. Meanwhile, grill the steak for 2-3 minutes on each side for medium-rare or cooked to your liking. Using tongs, sear the fat until golden, 30 seconds. Transfer to a plate and leave to rest for 5 minutes. No BBQ? Use fresh lemon cut into wedges. Heat a large frying pan over high heat with a drizzle of olive oil. When the oil is hot, cook the steak for 2-3 minutes or until cooked to your liking. Using tongs, sear the fat until golden, 30 seconds. Transfer to a plate and leave to rest for 5 minutes.

While the steak is resting, return the empty saucepan to a medium-high heat with the butter and a drizzle of olive oil. Cook the onion, stirring, until softened, 4-5 minutes. Add the garlic and cook until fragrant, 1 minute. Remove from the heat. Return the potato to the pan, then add the lemon zest, wholegrain mustard (see ingredients), sour cream and the salt. Season with pepper. Toss to combine.

Scoop out the avocado flesh, then thinly slice. In a medium bowl, add a good squeeze of the charred lemon juice and a drizzle of olive oil, then season with salt and pepper. Add the rocket leaves, tomato and avocado. Toss to combine and season to taste. Slice any remaining charred lemon into wedges.