Chicken A La Marengo

• 1 14-ounce can whole peeled tomatoes
• 1/3 cup chopped carrot
• 1/3 cup chopped celery
• 2/3 cup chopped onion
• 2 tablespoons chopped flat-leaf parsley
• Salt
• 2 tablespoons unsalted butter
• 3 tablespoons olive oil
• 1 clove garlic, crushed
• 1 4 1/2 pound chicken, cut into 4 pieces
• Freshly ground black pepper
• 1/2 pound white mushrooms, trimmed and quartered

1. Pour the can of tomatoes into a small saucepan. Crush the tomatoes using a potato masher or fork. Add the carrot, celery, onion and parsley. Bring to a boil, then reduce the heat and simmer until thickened and reduced to about 1 cup, about 40 minutes. Season with salt about halfway through.
2. Press through the fine disk of a food mill into a bowl, then stir in 1 tablespoon butter and check the seasoning. (Should make about 1 cup.)
3. Melt the remaining 1 tablespoon butter with the oil in a 12-inch saute pan or casserole over medium-high heat. Add the garlic. Season the chicken pieces with salt and pepper. Add the dark pieces to the pan. Once they begin to get crisp on the edges, reduce the heat to medium. After 5 minutes, add the breast pieces. Turn the chicken as it browns and remove the pieces to a platter as they finish cooking, 15 to 18 minutes total time. After 15 minutes, add the mushrooms to the pan, season them and cook until lightly browned and cooked through - they may need to cook for a few minutes after the chicken has been removed.
4. Remove the pan from the heat and spoon off all but 1 to 2 tablespoons of fat, Add 1 cup tomato puree to the mushrooms and stir up any bits stuck to the bottom of the pan. Simmer until the sauce thickens and forms a glaze with the fat in the pan. Taste and adjust the seasoning.
5. Spoon the sauce over the chicken.

tomatoes, carrot, celery, onion, flatleaf, salt, unsalted butter, olive oil, clove garlic, chicken, freshly ground black pepper, white mushrooms

Taken from food52.com/recipes/7639-chicken-a-la-marengo (may not work)