Tomatillo roast chicken

A week or so ago Alex bought tomatillos at the Mexican take out place/grocery store down the street, and I've just been looking at them and thinking what to do. I knew I wanted to do something with chicken, and last night I had no dinner plans. So I told Alex to bring home a chicken. I didn't want to make a salsa, and that's pretty much all I could find when thinking about things to do with tomatillos. I wanted more of a sauce, creamy and a little tart from the tomatillos, but also spicy. I settled on roasting, then pureeing. And oh, it was delicious. 
Tomatillo roast chicken

1 whole chicken, 3-4 pounds

2 T butter, melted

1 t chili

2 cloves garlic, minced

1 t cumin

1 t salt

ground pepper

4-6 tomatillos, quartered

1/2 onion, large dice

2 stalks celery, sliced

1 or 2 Thai chilis

6 cloves of garlic, whole

1/4 c water 

Heat the oven to 375. Combine the melted butter, chili, cumin, garlic, salt and pepper. Rub under the skin, all over the breast and legs. Sprinkle the skin with more salt and pepper. Combine the vegetables in a roasting pan, sprinkle with a little salt and pepper, and pour water over. Nestle the chicken in the middle, and roast for 45 minutes to an hour. Turn up the heat to 450, roast for about a half an hour longer, until the vegetables are soft and the chicken is done. Let the chicken rest and put all the veggies in the blender with their sauce, blend until smooth, and taste for salt. Serve over chicken.