Heat a medium saute pan or sauce pan over medium-high heat. Add half the vegetable oil, and half the butter.
Add chicken breast to a mixing bowl, season with salt and pepper; Mix well.
Add the chicken to the pan without over crowding; Sear all sides before removing the chicken and reserving.
Add the remaining oil, butter, garam masala, cayenne pepper, and cumin to the pan and toast spices for 1-2 minutes or until fragrent while mixing periodically.
Add the onions and garlic to the pan, saute for 4-5 minutes or until onions are translucent; Season with salt and pepper.
De-glaze the pan with heavy cream and tomato sauce; Mix until well incorporated and the sauce has a light red hue.
Bring the sauce to a boil and reduce to a simmer while stirring periodically.
Add the chicken back to the pan, and allow to simmer for 15 minutes to reduce and bring all the flavors together; Adjust seasoning with salt and pepper if needed.
Allow to cool, transfer into an airtight container and refrigerate until needed.