Preheat the oven to 220C, fan-forced. Line 2 oven trays with baking paper. Coarsely chop the cauliflower stem, then cut the head into florets. Put the cauliflower on a lined tray, drizzle with 3 tsp olive oil, season with salt and pepper and toss to coat. Roast for 20-22 mins until golden and tender.
Step 2 — Prep ingredients
Meanwhile, crush or finely chop the garlic. Thickly slice the cucumber. Coarsely chop the tomatoes. Coarsely chop the parsley leaves, discarding the stems. Finely grate the lemon zest, then juice.
Step 3 — Make kofta
Put the beef mince, garlic and kofta seasoning in a large bowl and season with salt and pepper. Using damp hands, combine well, then shape into 8 ovals.
Step 4 — Cook kofta
Heat a chargrill pan over high heat until hot. Drizzle the koftas with 2 tsp olive oil. Cook the kofta, turning occasionally, for 10-12 mins until browned. Transfer to the remaining lined tray and bake for 3-4 mins until cooked through. Halve the pita and enclose in foil. Heat in the oven for 8 mins or until softened and warmed through.
Step 5 — Make tahini sauce
While the kofta are cooking, put the tahini (see cooking tip) and 60ml (¼ cup) hot water in a bowl and stir until a thick paste forms. Add half the lemon zest and 1 tbs lemon juice and stir until smooth and creamy. Taste, then season with salt and pepper.
Step 6 — Toss salad and serve
Whisk the sumac, remaining lemon zest, remaining lemon juice and 2 tbs extra virgin olive oil in a large bowl and season with salt and pepper. Add cauliflower, cucumber, tomato and parsley and toss to combine. Divide the pita among plates. Fill with the kofta and half the salad. Drizzle with the tahini sauce and serve with remaining salad.