While your chicken is cooking, make the sauce. In a large pan, heat a drizzle of oil or butter and sauté the onion and garlic for 3–5 minutes, until softened and fragrant.
Add the tomato passata, dried fenugreek, kasoori methi, garam masala, chilli and a few tablespoons of the reserved marinade. Stir to combine.
Lower the heat and simmer gently for 15 minutes, until the sauce thickens slightly. Give it a quick blitz in a blender or a stick blender. If you want your sauce a bit chunkier, you can skip this step.
Add a few drops of lemon juice or vinegar, then whisk in the cold cubes of butter until the sauce turns glossy and rich.
Add the slightly underdone chicken to the sauce, coat it well, and simmer on low heat for about 7 minutes, until tender and fully cooked.
Stir in the cream, season to taste with salt and pepper, and mix until the sauce is silky smooth.
Remove from the heat and nestle in one or two drained burrata balls in the centre of the pan. Just before serving, tear them open and gently swirl them into the sauce until the cheese softens and melts.
Garnish with fresh coriander leaves if desired and serve immediately with naan or basmati rice to soak up every bit of that buttery, creamy sauce.