Smothered Chicken with Leeks and Mushrooms

3 tablespoons butter
2 tablespoons vegetable oil
One 3- to 3 1/2 pound chicken, cut into serving pieces
2 medium-size leeks (white part and about 1 inch of the green), washed well and cut into 1-inch thick rounds
3 tablespoons all-purpose flour
1/2 pound fresh mushrooms, sliced
1/8 teaspoon dried thyme, crumbled
Salt and black pepper to taste
1 1/2 cups chicken broth
1/2 cup half-and-half

1. Preheat the oven to 350 degrees. Grease a 2-quart casserole and set aside.

2. In a large heavy skillet, heat the butter and oil together over moderate heat until the butter melts, then brown the chicken pieces on all sides and transfer to the prepared casserole.

3. Add the leeks to the skillet, cover, and sweat till softened, about 5 minutes. Sprinkle the flour over the top, stir for 1 minute, add the mushrooms and thyme, season with salt and pepper, and stir for 5 minutes. Add the broth and half-and-half and cook, stirring, till the mixture begins to thicken. Pour the mixture over the chicken, cover, and bake till the chicken is tender, about 1 hour.

Serves 4.