Despite its Italian-sounding name, chicken tetrazzini is a wholly American invention. Freshly cooked pasta gets tossed in a creamy mushroom sauce and baked in a casserole with a crispy Parmesan breadcrumb topping. It's rich, hearty, and perfect for pleasing a crowd. If this ain't comfort food, we don't know what is.
Add pasta to boiling water and cook until al dente, 11-13 minutes. Drain in colander and rinse under cold water. This will stop cooking process. While pasta cooks, prepare ingredients.
Prepare the Ingredients
Mince garlic. Quarter mushrooms. Stem and mince parsley. Place breadcrumbs, Parmesan, and 2 tsp. olive oil in a small bowl and mix together. Rinse chicken and pat dry. On a separate cutting board, cut chicken into ½” dice. Season with ½ tsp. salt and ¼ tsp. pepper.
Cook the Vegetables
Heat 2 tsp. olive oil in a large pan over medium-high heat. Add mushrooms, parsley (reserving a bit for garnish), and garlic to hot pan and cook, stirring constantly, 30 seconds. Add butter to pan. Once butter is melted, stir in flour and cook, stirring constantly with a wooden spoon, until a light brown paste has formed and begins to smell nutty, 2 minutes. This is known as a roux and acts as a thickener for sauce.
Add the Chicken
Add milk, chicken, and chicken base to pan. Stir to combine and bring to a simmer. Once simmering, cook until sauce thickens, 5 minutes. Season with ½ tsp. salt and ¼ tsp. pepper.
Assemble and Bake Casserole
Add pasta to pan and mix together thoroughly. Transfer entire mixture to prepared casserole dish. Sprinkle breadcrumb-Parmesan mixture over casserole. Cover and bake 20 minutes. Remove from oven, uncover, and bake until golden brown, bubbly, and chicken reaches a minimum internal temperature of 165 degrees, 5-7 minutes.
Plate the Dish
Allow casserole to rest at least 5 minutes. Garnish with reserved parsley. Gather the family around the table and dig in!