Mix your chicken, fat free Greek yogurt, 1 teaspoon of garam masala, 1/2 a teaspoon of tumeric and 1/2 a teaspoon of cumin in a bowl until everything is well combined. You can leave this marinade for a few hours in the fridge if you have time but it's not necessary.
Heat a pan on a medium heat and spray well with 1 kcal spray.
Add the marinated chicken to the pan and fry for about 3 minutes on each side until starting to colour. Remove the chicken from the pan and leave aside (you will finish cooking it in the sauce in a while).
Add the pan back to the heat and add the butter.
Add the onion and cook for about 3-4 minutes until the onion is starting to soften.
Add the garlic, 1 teaspoon of garam masala and 1 teaspoon of cumin to the pan and stir well.
Add the peppers and mushrooms, and stir fry for 2-3 minutes.
Pour in the passata and bring the sauce to a simmer.
Add in the chicken and for about 8-10 minutes until the chicken is cooked throughout and the sauce is starting to thicken.
Stir in the cream and sweetener.
Season with salt and pepper to taste.
Serve with your favourite side such as rice/naan breads and a garnish of fresh coriander.