In a bowl, combine 1 tablespoon of the tomato paste, the garlic, ginger, garam masala, coriander, turmeric, cumin, 1¼ teaspoons of salt, and mix until a paste forms.
In another bowl, combine the yogurt, ½ teaspoon of salt, and half of the spice paste until well blended.
Using a knife, make shallow cuts in each chicken breast, then add the chicken to the bowl and coat it with the marinade.
Refrigerate for at least 30 minutes.
In a large saucepan, heat the vegetable oil and add the onion and chili peppers.
Add the remaining tomato paste and cook for 2 to 3 minutes, until the paste becomes a darker red. Add the remaining spice paste and continue stirring for another 2 to 3 minutes.
Next, add the tomato purée and ⅓ cup of water to the saucepan. Simmer, stirring frequently, for 10 to 12 minutes, until the sauce thickens.
Stir in the heavy cream and continue cooking over low heat for another 10 to 12 minutes.
Place the marinated chicken on a baking sheet and broil in the oven until it is almost cooked through, about 15 minutes. The chicken will not be fully cooked at this stage. It will finish cooking later.
Cut the chicken into bite-sized pieces. Add the chicken and the cilantro to the tomato sauce. Simmer over low heat.
Stir occasionally for about 10 minutes, until the chicken is fully cooked. Add ½ teaspoon of salt.
Serve with basmati rice and naan bread.