Chicken Tetrazzini Casserole

INGREDIENTS

1 lb. 

linguine

3 tbsp. 

butter, divided

2 c. 

mushrooms, thinly sliced

Kosher salt

Freshly ground black pepper

2 

cloves garlic, minced

1 lb. 

boneless skinless chicken breasts, cut into 1" pieces

2 tbsp. 

all-purpose flour

1 1/2 c. 

low-sodium chicken broth 

1 1/2 c. 

heavy cream

2/3 c. 

freshly grated Parmesan

DIRECTIONS

1. Preheat oven to 350°. Prepare linguine according to package instructions. Drain, reserving half a cup pasta water. 
2. In a large skillet over medium heat, melt 1 tablespoon butter. Add mushrooms and season with salt and pepper. Cook until mushrooms are mostly tender, 4 to 5 minutes, then add chicken. Season again with salt and pepper and cook, stirring occasionally, until chicken is lightly golden, 5 minutes. Add garlic and cook until fragrant, 1 minute more. Transfer mixture to a large plate or bowl. 
3. Return skillet to medium heat and melt remaining 2 tablespoons butter. Whisk in flour until completely combined, then slowly whisk in broth and heavy cream. Bring to simmer over medium heat, stirring occasionally and allowing sauce to thicken, about 10 minutes. 
4. Add pasta and chicken mixture to skillet and toss to combine. Add pasta water to loosen sauce if needed. Sprinkle with parmesan and bake until sauce is bubbling and cheese is golden, 25 minutes.