Ingredients

• 8 ounces uncooked pasta* (I used whole-wheat rotini)
• 1 large head of broccoli*, cut into bite-sized florets (about 1 pound of florets)
• 2 tablespoons butter or olive oil
• 1 small white onion, thinly sliced
• 8 ounces baby bella (cremini) mushrooms, thinly sliced
• 4 cloves garlic, minced
• 3 tablespoons flour
• 1 cup chicken or vegetable stock
• 1 1/2 cups milk
• 1 teaspoon Dijon mustard
• 1/2 teaspoon fine sea salt
• 1/4 teaspoon freshly-cracked black pepper
• 2 cups (8 ounces) shredded sharp cheddar cheese, divided
• 2 cups diced (or shredded) cooked chicken

Instructions

1. Preheat the oven to 400°F.
2. Cook the pasta. Bring a large pot of well-salted water to a boil and cook the pasta until al dente. About 1 minute before it finishes cooking, stir the broccoli florets into the same pot. Drain the pasta and broccoli together, then set aside.
3. Sauté the vegetables. In a large sauté pan over medium-high heat, melt the butter (or warm the oil). Add the sliced onion and cook for 3 minutes, stirring occasionally. Stir in the mushrooms and garlic, and continue cooking for 5 minutes, stirring occasionally, until the mushrooms are tender.
4. Build the sauce. Evenly sprinkle the flour over the vegetable mixture and stir to coat. Cook for 1 minute, stirring occasionally. Pour in the stock and stir until most lumps dissolve. Add the milk, Dijon mustard, salt, and pepper, stirring to combine. Continue cooking until the sauce reaches a simmer. Remove from heat and mix in 1 cup of the shredded cheddar until smooth. Taste and adjust seasoning with more salt and pepper if needed.
5. Assemble the casserole. In a 9 x 13-inch baking dish, combine the cooked pasta, broccoli, mushroom sauce, and chicken. Toss until evenly coated, then spread into an even layer.
6. Bake. Place the dish in the oven, uncovered, and bake for 15 minutes. Remove from the oven, sprinkle the remaining cheddar evenly over the top, and return to bake for 10 more minutes, or until the cheese is fully melted.
7. Serve. Enjoy warm, topped with extra black pepper or fresh herbs if desired.

• Pasta: Any variety works well — traditional semolina, whole-wheat, egg-based, gluten-free, or alternative-grain pasta.
• Broccoli: If preferred, substitute 1 pound of frozen broccoli florets (thawed) for fresh broccoli.