Homemade Chicken Doner Kebab

Puree the onion until completely smooth, then squeeze it through a fine sieve or cloth to remove as much liquid as possible, leaving behind the concentrated onion pulp.
Transfer the onion pulp to a large mixing bowl and combine it with the lamb, yoghurt, olive oil, garlic, and the spices. Mix thoroughly with your hands or a firm spoon until the mixture is sticky and uniform.
Place a sheet of baking paper on a flat surface. Spread the mixture on top and flatten it slightly with your hands or a rolling pin so it is thin enough to roll.
Place another sheet of baking paper on top of the flattened mixture to prevent sticking, then carefully roll it into a tight log using the top sheet to guide and compress it.
Preheat the oven to 200°C. Transfer the rolled doner onto a tray and bake for 20 minutes, or until fully cooked through but still tender.
Remove from the oven, unroll it gently, then break or slice it into thin doner-style strips.
Spread the strips out on the tray and broil (grill) them for 5 minutes at 250°C to caramelise the edges.
Once cooked allow it to rest briefly. Serve warm with naan or your preferred sides.