Baked Penne with Chicken, Spinach and Mushrooms

This dinner was a real hit! Luckily, this recipe makes enough for two casseroles--one for now, and one you can freeze for later. I plan to make this recipe again, substituting the spinach for peas, sun-dried tomatoes, or a variety of other vegetables.

4 tablespoons butter
coarse salt and ground pepper
1 pound whole wheat penne
1 teaspoon olive oil
2 boneless, skinless chicken breast halves (8 ounces each), halved horizontally
1/2 cup plus 2 tablespoons all-purpose flour (spooned and leveled)
4 garlic cloves, minced
6 cups skim milk
10 ounces white mushrooms, trimmed and thinly sliced
10 ounces frozen spinach, thawed and drained
1 1/2 cups shredded provolone (6 ounces)
1 cup finely grated Parmesan (4 ounces)

Preheat oven to 400. Butter two shallow 2-quart baking dishes. In a large pot of boiling salted water, cook pasta 3 minutes short of al dente; drain pasta, and return to pot.

Season chicken with salt and pepper. I cooked the chicken on my George Foreman grill, but if you don't have one of those, feel free to cook in a skillet over medium heat. The fillets should take about 3-5 minutes per side, depending on thickness. Place cooked chicken fillets on a paper towel and let cool, about 5 to 10 minutes. Cut the fillets lengthwise into slices, then crosswise.

In a heavy pot, melt butter over medium. Add flour and garlic; cook, whisking, 1 minute. While whisking, gradually add milk; bring to a simmer, whisking frequently. Add mushrooms and spinach; cook 1 minute. Off heat, gradually stir in provolone.

Add chicken and pasta to pot; season with salt and pepper. Divide pasta mixture between baking dishes; sprinkle each with cup Parmesan.

Bake, uncovered, until top is golden and bubbling, about 25 minutes. Let stand 5 minutes before serving.

Prepare through step 4; let cool. Cover tightly with foil, and freeze, up to 3 months.

To prepare the frozen casserole, preheat oven to 400, and bake (still covered in foil) on a rimmed baking sheet until center is hot, about 1 1/2 hours. Remove foil; bake until golden, about 15 minutes more.