Wild Rice Casserole with Chicken, Mushrooms and Broccoli

Nothing innovative about this casserole, but damn, is it good.

Wild Rice Casserole with Chicken, Mushrooms and Broccoli 
4 cups water 1 cup wild rice, rinsed
1 tablespoon olive oil
2 celery stalks, diced
2 carrots, diced
1 medium yellow onion, diced
½ pound cremini mushrooms, chopped
1 tablespoon fresh thyme
1 teaspoon ground mustard
1 teaspoon poultry seasoning
3 tablespoons butter
3 tablespoons all-purpose flour
2 cups low-sodium chicken broth
½ cup nonfat milk
½ pound broccoli crowns, chopped
1 pound cooked, chopped chicken meat
Salt and pepper
1 cup grated sharp cheddar

Preheat oven to 350 degrees.

In a medium saucepan, bring rice and water to boil. Reduce heat, cover and cook rice until tender, about 40 minutes or so. Drain well.

While rice is cooking, warm olive oil in large skillet over medium heat. Add celery, carrots, onion and thyme and sauté for 5 minutes, stirring occasionally, until vegetables start to soften. Stir in the mushrooms, ground mustard and poultry seasoning and sauté for another 2-3 minutes. Add butter, flour and chicken broth and bring to a simmer. Cook mixture for 5 minutes, stirring occasionally, until sauce thickens a bit. Stir in milk and continue simmering for another 5 minutes. Remove from heat, season with salt and pepper, and stir in broccoli, chicken and rice. Transfer mixture to a 9-by-13 glass baking dish, top with cheese, and bake, uncovered, for 20 minutes. Remove from oven and enjoy.