Wondering what to do with Thanksgiving leftovers? Turn leftover turkey into this cozy, crowd-pleasing Turkey Tetrazzini casserole in under an hour. Scroll for the easy recipe!

Golden, bubbling cheese pulling into long, glorious strands while a rich roasted-garlic and brown-butter sauce clings to every single ribbon of tender pasta is what makes this Turkey Tetrazzini an absolute showstopper on any dinner table!

About This Dish & How It Tastes!

Before we grab our aprons and start chopping, let us talk about why this specific recipe tastes worlds better than every other version out there!

Most recipes rely on canned condensed soup and watery, under-browned mushrooms, which leaves you with a flat, one-note pasta bake. Instead, we prepare our sauce by browning real unsalted butter until it smells like toasted hazelnuts, then whisking in sweet, jammy roasted garlic and a splash of dry sherry for brightness.

The flavor is rich, nutty, velvety, and layered with umami from golden-seared cremini mushrooms and aged Parmesan, balanced by a bright pop of fresh lemon zest and thyme.

On top of all that creamy, tender linguine and juicy turkey sits a golden-brown crust of buttery toasted brioche crumbs and nutty Gruyère cheese, giving you an incredible contrast of silky pasta underneath and a loud, buttery crunch in every single bite!

Ingredients

For the Pasta & Turkey Base

• 12 oz (340 g) dry linguine or fettuccine (broken in half so nobody splashes cream sauce on their shirt while twirling.)
• 4 cups (about 20 oz / 565 g) cooked, shredded or bite-sized cubed turkey (a mix of juicy dark meat and tender breast meat works best.)
• 1 tablespoon kosher salt (for pasta water)

For the Brown Butter & Caramelized Mushroom Sauce

• 1 lb (450 g) fresh cremini (baby bella) mushrooms, wiped clean and sliced 1/4-inch thick
• 6 tablespoons (85 g) unsalted butter, divided (2 tablespoons for searing mushrooms, 4 tablespoons for making brown butter)
• 1 tablespoons extra-virgin olive oil
• 1 medium yellow onion, finely diced (about 1 cup)
• 6 large cloves garlic, finely minced
• 1 tablespoon roasted garlic paste (or 1 whole head of garlic roasted at 400°F for 35 minutes and squeezed out, or 6 extra cloves slowly toasted in butter.)
• 1/3 cup (80 ml) dry sherry or dry white wine (such as Pinot Grigio or Sauvignon Blanc)
• 1/3 cup (42 g) all-purpose flour
• 2.5 cups (600 ml) low-sodium turkey stock or chicken bone broth, warmed
• 1 cup (240 ml) heavy whipping cream, at room temperature
• 1/3 cup (80 g) full-fat sour cream or crème fraîche (for a subtle tang that cuts through the richness.)
• 1 tablespoon fresh thyme leaves, finely chopped
• 1/2 teaspoon freshly grated nutmeg (do not skip fresh nutmeg here, it makes cream sauces sing.)
• 1 teaspoon kosher salt, plus more to taste
• 3/4 teaspoon freshly cracked black pepper
• 1 cup (100 g) freshly grated Gruyère cheese, divided (half for the sauce, half for the topping)
• 3/4 cup (75 g) freshly grated Parmigiano-Reggiano cheese, divided
• 3/4 cup (100 g) frozen petite green peas (no need to thaw!)

For the Crispy Lemon-Herb Brioche Topping

• 1.5 cups (90 g) fresh coarse brioche or sourdough breadcrumbs (or panko breadcrumbs if you are in a rush.)
• 2 tablespoons (28 g) unsalted butter, melted
• 2 tablespoons fresh flat-leaf parsley, finely minced
• 1 teaspoon freshly grated lemon zest
• Pinch of flaky sea salt

Yield: 6 to 8 generous servings!

Prep Time: 30 minutes
Cook Time: 35 minutes
Total Time: 1 hour 5 minutes
Oven Temperature: 375°F (190°C)

How to Make Turkey Tetrazzini

Start by preheating your oven to 375°F (190°C) and greasing a 9×13-inch ceramic or glass baking dish with a generous swipe of butter, then bring a large pot of water with 1 tablespoon of kosher salt to a rolling boil.

Drop in the broken linguine and cook it for 2 minutes less than what the package instructions recommend, usually around 7 to 8 minutes, because I learned the hard way years ago that fully cooked pasta turns into mush once it bakes in the oven, whereas slightly undercooked, super al dente noodles drink up that velvety sauce in the oven and come out with the ideal bite.

Drain the pasta into a colander and toss it with a tiny drizzle of olive oil so the strands do not fuse into a giant noodle brick while we prepare our sauce.

Next, heat a large, heavy-bottomed Dutch oven or deep 12-inch skillet over medium-high heat, add 2 tablespoons of butter along with 1 tablespoon of olive oil, and wait until the butter foams and subsides before scattering in the sliced cremini mushrooms.

Here is my biggest rule in the kitchen: do not touch or stir those mushrooms for the first 4 minutes, and do not salt them yet, because salting early draws out moisture and steams them into rubbery gray slugs instead of giving you deeply browned, nutty edges.

Once the undersides of the mushrooms are mahogany-brown and smell earthy and rich, give them a toss, cook for another 3 to 4 minutes until golden all over, and transfer them to a warm plate.

Turn the heat down to medium and drop the remaining 4 tablespoons of butter right into that same skillet, swirling the pan occasionally for about 3 minutes while the butter melts, crackles, foams, and starts showing little toasted golden-brown milk-solid flecks at the bottom that smell just like roasted pecans.

The very second you smell that nutty aroma and see amber flecks, toss in the diced yellow onion right away so the moisture from the onion stops the butter from burning.

Cook the onion for 4 to 5 minutes until translucent and soft around the edges, then stir in minced garlic, roasted garlic paste, and fresh thyme leaves for 60 seconds until your whole kitchen smells like a five-star bistro!

Pour in dry sherry or white wine to deglaze the pan, using a wooden spoon to scrape up every single browned bit stuck to the bottom of the pot, because those caramelized bits hold pure flavor gold.

Let the wine bubble and reduce for about 2 minutes until almost syrupy, then sprinkle all-purpose flour evenly over the onions and stir constantly for 90 seconds until the paste looks like wet golden sand and no longer smells like raw flour.

Slowly pour in warmed turkey stock about half a cup at a time while whisking vigorously with your other hand so not a single lump dares to form, then whisk in the room-temperature heavy cream.

Let the sauce simmer gently over medium-low heat for 4 to 5 minutes until it thickens enough to coat the back of a spoon, when you run your finger down the back of that spoon, the line should hold clean without running.

Remove the pot from the heat and whisk in the sour cream, freshly grated nutmeg, kosher salt, cracked black pepper, half of your grated Gruyère (1/2 cup), and half of Parmigiano-Reggiano (about 1/2 cup), stirring until the cheeses melt into a glossy, silky ribbon.

Notice how I took the pot off the burner before adding the cheese, and please do not skip this step, because boiling cheese directly over high heat breaks the dairy proteins and makes the sauce grainy instead of velvety smooth.

Fold drained linguine, browned mushrooms, shredded turkey, and frozen petite peas right into the pot, using tongs to lift and turn everything gently for a full minute until every nook and cranny is coated in that glorious brown-butter cream sauce, and taste a strand right now to see if you want an extra pinch of salt or pepper.

Scrape the entire mixture into your buttered 9×13-inch baking dish and spread it into an even layer, making sure to tuck any stray noodle tips down into the sauce so they do not dry out in the oven.

In a small bowl, toss your coarse brioche breadcrumbs with 2 tablespoons of melted butter, minced parsley, fresh lemon zest, a pinch of flaky salt, and the remaining Gruyère and Parmigiano-Reggiano cheeses, rubbing the mixture lightly between your fingertips until the crumbs glisten.

Scatter this cheesy, lemony crumb topping evenly across the top of the dish and slide it onto the middle rack of your 375°F oven for 25 to 30 minutes, watching for the edges to bubble vigorously and the top to turn a deep, toasted golden-brown.

If you love extra crispy edges like I do, flick on your oven broiler for the final 60 to 90 seconds while watching through the oven window like a hawk, then pull the dish out and let it rest for 10 full minutes on a cooling rack so the bubbling sauce sets into creamy perfection before you scoop in.

Serving Suggestions!

• Crisp Shaved Fennel & Apple Salad: Serve your warm pasta alongside a cold, crunchy salad of shaved fennel, Honeycrisp apple slices, baby arugula, and a sharp Dijon-lemon vinaigrette to slice right through the rich brown-butter cream sauce!
• Charred Garlic Green Beans or Broccolini: Roast fresh broccolini or French green beans on a sheet pan at 400°F with olive oil, sea salt, and crushed red pepper flakes, then finish with a squeeze of fresh lemon juice for a vibrant green side!
• Cranberry-Orange Relish on the Side: If you are making this after a holiday feast, a spoonful of tart, ruby-red cranberry sauce right next to your creamy pasta adds a bright, tangy pop of flavor that pairs like magic!
• Wine Pairing: Pour a chilled glass of unoaked Chardonnay, a crisp Sauvignon Blanc, or a light-bodied Pinot Noir to complement the caramelized mushrooms and nutty Gruyère!

Once you pull this bubbling, golden-crusted turkey tetrazzini out of the oven and hear that first crunch of the lemon-herb brioche topping under your serving spoon, you might actually start roasting extra birds in the middle of July just to have an excuse to make it again!

Every creamy, cheesy forkful of this homemade turkey tetrazzini brings together nutty brown butter, sweet roasted garlic, and tender pasta in a way that turns humble leftovers into the most requested dinner in your repertoire!

So grab a fork, claim a crispy corner piece before someone else beats you to it, and let me know in the comments how fast your baking dish disappeared!