Step 1

Preheat oven to 375 degrees F (190 degrees C).

Step 2

Melt a few tablespoons of butter in a skillet over medium heat. Stir in onion and garlic, and cook slowly until the onion caramelizes to a dark brown, about 15 minutes.

Step 3

Meanwhile melt the remaining butter in a saucepan over medium-high heat along with the tomato sauce, heavy cream, salt, cayenne pepper, and garam masala. Bring to a simmer, then reduce heat to medium-low; cover, and simmer for 30 minutes, stirring occasionally. Then stir in caramelized onions.

Step 4

While the sauce is simmering, toss cubed chicken breast with vegetable oil until coated, then season with tandoori masala and spread out onto a baking sheet.

Step 5

Bake chicken in preheated oven until no longer pink in the center, about 12 minutes. Once done, add the chicken to the sauce and simmer for 5 minutes before serving.