This creamy chicken tetrazzini earned a permanent spot in my dinner rotation the first time I served it on a rainy Sunday. I had a leftover rotisserie chicken and a half box of pasta in the pantry, and the result was a bubbly, golden-topped casserole that made the whole kitchen smell like comfort. The sauce is silky and rich without feeling heavy, the mushrooms bring savory depth, and the mozzarella melts into long, satisfying strands with every forkful.

I especially love how forgiving this dish is. If you have time, cook chicken breast and chop it. If not, rotisserie chicken keeps things simple and weeknight-friendly. The pasta bakes to perfectly tender, the lemon brightens the cream, and a shower of parsley makes it feel fresh. The first time I made it, my family hovered like they were waiting to open presents. No one left a bite behind, and the leftovers reheated perfectly the next day. That is the kind of reliability I look for in a casserole I will make again and again.

Ingredients

• Linguine or spaghetti: Choose bronze-cut durum wheat pasta like De Cecco or Rummo. It grips the sauce better and does not bloat during baking. Cook just shy of al dente.
• Rotisserie chicken: Shredded or diced chicken makes this speedy. Use moist, well-seasoned meat; a mix of white and dark meat adds flavor and tenderness.
• Button mushrooms: Thickly sliced for meaty texture. Look for firm caps with dry surfaces; avoid slimy mushrooms. Browning them builds savory, earthy depth.
• Onion: A medium yellow onion adds sweetness and aroma. Dice finely so it softens quickly and disappears into the sauce for a smooth bite.
• Garlic: Freshly minced cloves release fragrant oils that perfume the sauce. Avoid jarred garlic here; the taste is sharper and less rounded.
• Low-sodium chicken broth: A clean, savory base that lets the cream and lemon shine. Low-sodium lets you season to taste without oversalting.
• Half and half: Creamy body without heaviness. If substituting, use equal parts whole milk and heavy cream to mirror the texture and richness.
• Mozzarella: Shred it yourself for the best melt. Pre-shredded can contain starches; freshly grated creates silky, stretchy pull.

Instructions

Preheat and prepare the dish: Preheat the oven to 350°F. Generously butter a 9 by 13 inch casserole dish to prevent sticking and promote an evenly browned edge. Set a rack in the center of the oven for even heat circulation during baking. Cook the pasta: Bring a large pot of well-salted water to a rolling boil. Add pasta and cook until barely al dente, 1 to 2 minutes shy of package time. Reserve 1/2 cup pasta water, drain, and return pasta to the warm pot. Partially cover to keep it from drying. Sauté mushrooms and aromatics: Heat olive oil in a large skillet over medium-high. Add mushrooms and cook about 3 minutes until they release moisture and begin to brown. Stir in onion; cook 5 to 7 minutes until soft and golden. Add garlic and cook 1 minute until fragrant. Set aside. Build the creamy sauce: In the same pot, melt butter over medium heat. Whisk in flour and cook 1 to 2 minutes until lightly golden and nutty. Gradually whisk in broth, lemon juice, salt, and pepper until smooth. Whisk in half and half and bring to a gentle simmer until slightly thickened. Combine the casserole: To the pasta pot, add chicken, the mushroom-onion mixture, parsley, and all the sauce. Toss until everything is coated. If a bit tight, loosen with 1/2 cup reserved pasta water. Spread evenly into the prepared casserole dish. Bake and finish: Top generously with mozzarella. Cover with foil and bake 20 minutes at 350°F. Uncover and bake 15 minutes more. For color, broil 1 to 2 minutes, watching closely. Rest 5 minutes, then garnish with parsley and serve.

Storage Tips

For make-ahead, assemble the casserole without baking, cover tightly, and refrigerate up to 5 days. When ready, top with mozzarella and bake as directed, adding a few extra minutes if very cold. For freezing, wrap the unbaked dish in two layers of plastic and one of foil and freeze up to 6 months. Thaw overnight in the refrigerator before baking. Leftovers should cool completely before storing in airtight containers; refrigerate up to 5 days or freeze up to 6 months. Reheat covered at 350°F until hot in the center, or microwave in 1 minute bursts, stirring between intervals.

Ingredient Substitutions

No half and half? Use 1 cup heavy cream plus 1 cup whole milk. Swap mozzarella with provolone or Monterey Jack for a similar melt, or add 1/4 cup grated Parmesan to the top for extra savoriness. Linguine and spaghetti are interchangeable; short shapes like penne or rotini also work, using 12 ounces. If you are out of rotisserie chicken, cook 1.5 pounds chicken breast as noted, or use leftover turkey in an equal amount. Low-sodium broth is key; if using regular, reduce added salt and taste as you go.

Serving Suggestions

Serve this bubbling hot with a crisp green salad dressed simply with lemon and olive oil to balance the richness. Garlic bread or a warm baguette makes a great partner for swiping through the creamy sauce. For color and brightness, garnish with fresh parsley and a light squeeze of lemon at the table. If you are hosting, pair with roasted green beans or a sheet pan of broccoli tossed with olive oil and black pepper. A dry white wine like Pinot Grigio complements the sauce beautifully.

Cultural Background

Tetrazzini is an Italian-American classic named after the soprano Luisa Tetrazzini, popularized in the early 1900s. While it borrows Italian pantry staples like pasta and Parmesan, the creamy baked casserole format with mushrooms and poultry is distinctly American. Versions vary across the country; some include peas or sherry, others use Parmesan-heavy toppings or bread crumbs. This version leans into a smooth, velvety sauce with lemon for lift and mozzarella for a stretchy, family-friendly finish.

Seasonal Adaptations

In spring, add 1 cup blanched peas or asparagus tips to the mix before baking. Summer calls for a handful of chopped basil and a few halved cherry tomatoes stirred through after baking for freshness. In fall, swap button mushrooms for cremini and add a pinch of nutmeg to the sauce. For winter and holidays, use leftover turkey in place of chicken and sprinkle the top with 1/4 cup grated Parmesan for a festive, golden crust.

Meal Prep Tips

Divide the assembled casserole between two 8 by 8 inch pans for flexible weeknight dinners. Label with date and baking instructions, then freeze. For individual lunches, portion into microwave-safe containers and add a splash of broth when reheating to keep it creamy. If baking from chilled, remove the dish from the refrigerator while the oven preheats to reduce thermal shock and promote even heating. Keep a bit of extra broth or milk on hand to stir into leftovers as they reheat.

There is something wonderfully reassuring about a casserole that can be assembled in minutes and delivers rich, cozy flavor every time. Make it once, and it will become the dish you rely on for company, comfort, and everything in between.