Butter Chicken (riff thereof)

I came across a recipe called Butter Chicken in a recent Penzey's Spices catalog. The titleimmediately caught my attention, but then I accidentally threw the magazine away. No!!

I went to the trusty Internet, but I could not find the exact recipe. I did find enough other versions of it to create a sort of composite of what butter chicken ought to be. Then I took that idea and threw it away, creating some new amalgam out of what I had in the kitchen. The result was one of only 2 successful curries I've ever made. I have no idea what aspect of this made it work, so I've listed everything, though the odds that I will ever make it exactly like this again are very slim indeed.

Ingredients:

2 boneless, skinless chicken breasts
2 medium yellow onions
1 red bell pepper
2 garlic cloves
5 tomatillos
1 1/2 tsp garam masala (a spice blend available at most grocery stores)
3/4 tsp Balti curry powder, available from Penzey's
1/4 tsp cinnamon
1/4 tsp coriander
1/4 tsp cumin
1/2 tsp ground ginger
5 tbsp butter
1/2 cup tomato sauce
1/2 cup water
1/2 cup greek yogurt

Saute the chicken over medium-high heat until browned. Remove to a cutting board and chop.

Chop the vegetables and saute over medium heat in that same pan, with the butter. This incorporates any tasty browned bits left in the pan. When the vegetables are tender, add the spices and cook for another minute.

Add the tomato sauce and water, and simmer until vegetables are soft and the tomatillos begin to break down. Then remove the vegetable mixture to a blender, add the yogurt, and puree.

Combine the chicken and the sauce, and there you go!