This is a simple and amazing version of butter chicken, with a silky and gorgeously spiced sauce!
Get out a sturdy dutch oven. Heat one tablespoon of the butter and the olive oil in it over medium high heat. Brown the chicken in it unti just cooked, then add in the onion and garlic. Let them soften for a couple of minutes. While they soften, season the mixture with the garam marsala, curry powder, chili powder, paprika, salt and pepper. Finally, add in the remaining butter, tomato sauce, half and half, and Greek yogurt. Let it gently bubble and develop flavor for 15 minutes, stirring often.
Once the 15 minutes are up, stir the water and corn starch together in a bowl. Pour it into the pot and stir it in well. Let the sauce thicken and develop more flavor for another 15 minutes. Then it's all set, simple as that! Serve a generous amount over rice and scoop it up with warm naan bread. Enjoy!!