Preheat your oven to 350°F (175°C).

Cook the pasta according to package instructions, then drain and set aside.

In a large skillet, melt the butter over medium heat. Add the chopped onions and minced garlic, sautéing until they become translucent.

Toss in the sliced mushrooms and cook them until softened and fragrant, about 3-4 minutes.

Stir in the flour and let it cook for 1-2 minutes. Gradually whisk in the cream or chicken broth, stirring continuously until the mixture thickens.

Add the shredded chicken and half of the cheddar cheese. Season with salt and pepper, and mix well to combine.

Fold the sauce into the cooked pasta until every noodle is coated.

Transfer the mixture to a greased baking dish. Top with the remaining cheddar cheese and breadcrumbs if you desire that extra crunch.

Bake for 25-30 minutes, or until the top is bubbly and golden-brown.

Allow the dish to cool for a few minutes before serving. Enjoy!