Thinly slice the onion with a sharp knife or mandoline. Combine 1 tsp sugar and 2 tsp white wine vinegar in a bowl and stir in the onion. Set aside to pickle, tossing occasionally, until needed. Finely chop the tomato. Pick the parsley leaves, discarding the stems.
Step 2 — Make sumac yoghurt
Combine the yoghurt, sumac and 2 tsp water in a bowl. Season with salt and pepper.
Step 3 — Cook lamb mixture
Heat a drizzle of olive oil in a large frypan over high heat. Cook the lamb mince, breaking up the lumps with a spoon, for 3-4 mins until browned. Reduce the heat to medium-high, add the Turkish seasoning and 2 tbs water and bring to a simmer. Cook, stirring, for 1-2 mins until slightly reduced.
Step 4 — Wilt spinach
Add the spinach to the lamb mixture and cook, stirring, for 30 secs or until wilted. Remove from the heat.
Step 5 — Warm tortillas
Put the tortillas on a plate, slightly overlapping, and microwave for 30 secs or until warmed through.
Step 6 — Get ready to serve
Divide the tortillas, lamb mixture, tomato and drained pickled onion among plates. Drizzle over the sumac yoghurt and scatter with the parsley leaves to serve.