Marinate the Chicken: In a medium bowl, combine all the marinade ingredients: Greek yoghurt, lemon juice, grated ginger, crushed garlic, turmeric, garam masala, Kashmiri chilli powder, and salt. Add the chicken chunks and stir well to ensure every piece is thoroughly coated. Cover the bowl and refrigerate for at least 2 hours, or overnight for the best results.

Cook the Chicken: Preheat your grill to a medium-high heat. If you don't have a grill, a very hot griddle pan or frying pan will work. Thread the marinated chicken onto metal or pre-soaked wooden skewers. Place under the grill for 8-10 minutes, turning halfway through, until cooked through and nicely charred in places. Alternatively, pan-fry in a little oil for 4-5 minutes on each side. Set the cooked chicken aside.

Start the Sauce Base: While the chicken is cooking, heat the oil or ghee in a large, heavy-based pan or casserole dish over a medium heat. Add the finely chopped onion and cook gently for 8-10 minutes, stirring occasionally, until it's soft, sweet, and translucent. This slow cooking builds a crucial flavour foundation.

Add the Aromatics: Add the crushed garlic and grated ginger to the pan with the onions. Cook for another 2 minutes, stirring constantly, until fragrant. Be careful not to let them burn.

Toast the Spices: Add the ground cumin, ground coriander, garam masala, and turmeric to the pan. Stir and cook for 1 minute until their aroma is released. This toasting step is vital for a deep, complex masala recipe.

Create the Tomato Sauce: Pour in the tinned tomatoes (or passata) and the sugar. Stir everything together, scraping any spices from the bottom of the pan. Bring to a gentle simmer, then reduce the heat to low, cover, and let it cook for 10-12 minutes. The sauce should thicken and the colour will deepen.

Combine and Finish: Remove the cooked chicken from the skewers and add it to the simmering tomato sauce. Stir to coat the chicken pieces. I find that letting it simmer gently for another 5 minutes at this stage really allows the flavours to meld together.

Add the Cream: Turn off the heat and stir in the double cream. Do not let the sauce boil after adding the cream, as it can split. Season with salt to your liking.

Serve: Garnish your creamy chicken curry with a generous sprinkle of fresh, chopped coriander and serve immediately.