Marinate the Chicken: In a medium mixing bowl, combine all the marinade ingredients: the yoghurt, lemon juice, ginger, garlic, garam masala, turmeric, cumin, chilli powder, and salt. Add the chicken pieces and stir until every piece is thoroughly coated. Cover the bowl and place it in the fridge to marinate for at least 1 hour, or up to 8 hours for an even more flavourful result.

Cook the Chicken: Heat 1 tbsp of the vegetable oil in a large, heavy-based frying pan or skillet over a medium-high heat. Remove the chicken pieces from the marinade, shaking off any excess (reserve the leftover marinade for now). Place the chicken in the hot pan in a single layer – you may need to do this in two batches. Cook for 3-4 minutes per side, until the chicken is golden brown and slightly charred in places. It doesn't need to be cooked all the way through at this stage. Set the cooked chicken aside on a plate.

Start the Sauce Base: Reduce the heat to medium. Add the remaining 1 tbsp of oil and the butter to the same pan. Once the butter has melted, add the finely chopped onion. Sauté for 8-10 minutes, stirring occasionally, until the onion is soft, translucent, and just starting to turn golden at the edges.

Bloom the Spices: Add the crushed garlic and grated ginger to the pan and cook for another minute until fragrant. Then, stir in the ground coriander, ground cumin, and turmeric powder. Cook for 30 seconds, stirring constantly, until the spices release their aroma. This step, known as blooming, is vital for a deep-flavoured sauce.

Create the Sauce: Pour the tinned tomatoes into the pan, along with the sugar (if using) and any leftover marinade from the chicken bowl. Stir everything together, scraping up any browned bits from the bottom of the pan. Bring the sauce to a gentle simmer.

Simmer and Combine: Reduce the heat to low, cover the pan, and let the sauce simmer for 10-12 minutes. This allows the flavours to meld together. What works best for me is using a splatter guard if I want to reduce the sauce a little further without covering it completely.

Finish the Dish: Return the partially cooked chicken tikka pieces (and any juices from the plate) to the pan with the sauce. Stir to combine, then pour in the double cream. Stir gently and let it heat through for another 2-3 minutes until the chicken is cooked through and the sauce is hot. Be careful not to let it boil once the cream is added.

Serve: Taste the sauce and adjust seasoning if needed. Garnish generously with freshly chopped coriander and serve immediately with hot basmati rice and warm naan bread.