Creamy Turkey Tetrazzini with Mushrooms and Peas

Why You’ll Love This Recipe

• Comforting, creamy, and deeply savory with roasted turkey, mushrooms, and Parmesan.
• Smart make-ahead casserole that feeds a crowd and reheats beautifully.
• Balanced textures: silky sauce, tender spaghetti, and a crunchy buttered breadcrumb lid.
• Flexible: swap in chicken, different veggies, or use up holiday leftovers.

Grocery List

• Produce: Cremini mushrooms, shallot (or onion), garlic, lemon, fresh thyme, parsley
• Dairy: Butter, whole milk, heavy cream, Parmesan
• Pantry: Spaghetti, chicken/turkey stock, flour, panko breadcrumbs, olive oil, frozen peas, dry sherry/white wine (optional), Dijon, salt, pepper, nutmeg

Full Ingredients

Pasta & Mix-Ins

• 12 oz dry spaghetti
• 3 cups cooked roasted turkey, shredded or cut into 1/2-inch pieces (about 1 lb)
• 12 oz cremini mushrooms, trimmed and sliced 1/4-inch thick
• 1 cup frozen peas, thawed
• 1 large shallot (or 1/2 small yellow onion), finely minced
• 3 garlic cloves, minced
• 1 tbsp olive oil
• 1 tbsp unsalted butter (for sautéing)
• Kosher salt and freshly ground black pepper

Parmesan Cream Sauce

• 4 tbsp unsalted butter
• 1/4 cup all-purpose flour
• 1/4 cup dry sherry or dry white wine (optional but classic)
• 2 cups low-sodium chicken or turkey stock
• 1 cup whole milk
• 1/2 cup heavy cream
• 1 cup finely grated Parmesan cheese (about 2 oz)
• 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
• 1/8 tsp ground nutmeg
• 1 tsp Dijon mustard (optional, for brightness)
• 1 tsp finely grated lemon zest + 1–2 tsp fresh lemon juice, to taste

Crunchy Buttered Breadcrumb Topping

• 1 cup panko breadcrumbs
• 2 tbsp unsalted butter, melted
• 1/4 cup finely grated Parmesan
• Pinch kosher salt and black pepper

To Finish

• Chopped fresh parsley, for garnish
• Nonstick spray or butter, for greasing the baking dish

Step-by-Step Instructions

Step 1: Preheat and prep the dish

Set a rack in the center of the oven and preheat to 375°F. Lightly butter or spray a 9×13-inch baking dish. Bring a large pot of well-salted water to a boil (about 1 tablespoon salt per 4 quarts water). Gather and measure all ingredients so the recipe moves smoothly.

Step 2: Cook spaghetti to shy al dente

Add the spaghetti to the boiling water and cook until 2 minutes less than the package time; you want it quite firm so it finishes in the sauce. Reserve 3/4 cup pasta cooking water, then drain. Toss the drained pasta with a teaspoon of olive oil to prevent sticking and set aside.

Step 3: Sauté mushrooms and aromatics

In a large skillet over medium-high heat, add 1 tbsp butter and 1 tbsp olive oil. When shimmering, add the mushrooms and 1/2 tsp salt. Cook, stirring occasionally, until they release their moisture and develop deep golden edges, 7–9 minutes. Stir in the minced shallot and cook 2 minutes more. Add the garlic and cook just until fragrant, 30 seconds. Transfer the mixture to a bowl.

Step 4: Build a silky Parmesan cream

In the same skillet over medium heat, melt 4 tbsp butter. Sprinkle in the flour and whisk constantly for 1 minute to form a smooth roux. If using, splash in the sherry or wine and whisk until mostly absorbed, 30–60 seconds. Gradually whisk in the stock, then the milk and cream. Bring to a gentle simmer and cook, whisking, until the sauce thickens enough to coat the back of a spoon, 4–6 minutes.

Reduce heat to low and whisk in 1 cup Parmesan, thyme, nutmeg, Dijon (if using), and lemon zest. Taste and season with 1 tsp kosher salt and several grinds of pepper, adjusting as needed. The sauce should be pourable; use a splash of reserved pasta water to loosen if too thick.

Step 5: Combine turkey, peas, and pasta

Return the mushroom mixture to the skillet along with the turkey and peas. Stir until everything is coated and warmed through, 1–2 minutes. Fold in the spaghetti, tossing to coat evenly. Add additional reserved pasta water, a few tablespoons at a time, until the sauce clings silkily to the pasta without feeling stodgy. Stir in 1–2 tsp lemon juice to brighten.

Step 6: Assemble and add the crunchy lid

Transfer the mixture to the prepared baking dish and spread in an even layer. In a small bowl, mix the panko, melted 2 tbsp butter, 1/4 cup Parmesan, and a pinch of salt and pepper. Sprinkle evenly over the casserole to form a generous, even crumb layer.

Step 7: Bake, rest, and serve

Bake until the casserole is bubbling around the edges and the topping is deeply golden, 25–30 minutes. If the top browns too quickly, tent loosely with foil. Let rest 10 minutes to set. Sprinkle with chopped parsley and serve warm.

Pro Tips

• Cook pasta 2 minutes shy of al dente; it will finish perfectly in the sauce without going mushy.
• For deeply savory mushrooms, avoid crowding the pan and salt early to drive off moisture.
• Season the sauce gradually. Using low-sodium stock lets you control salt at the end.
• Adjust consistency with reserved pasta water. The sauce should be glossy and lightly fluid before baking.
• For extra crisp topping, broil the casserole 1–2 minutes at the end, watching closely.

Variations

• Rotisserie Chicken Tetrazzini: Swap turkey with shredded rotisserie chicken in equal measure.
• Green Veggie Twist: Use blanched chopped broccoli or asparagus in place of peas; add a squeeze of lemon to keep it bright.
• Gluten-Free: Use gluten-free spaghetti and panko; thicken the sauce with 1:1 rice flour or a gluten-free all-purpose blend.

Storage & Make-Ahead

Refrigerate leftovers in an airtight container for up to 4 days. Reheat covered at 350°F for 20–25 minutes (uncover and broil briefly to re-crisp the topping), or warm individual portions in the microwave until hot. To make ahead, assemble up to the topping, cover, and refrigerate for up to 24 hours; add the breadcrumbs just before baking and increase bake time to 35–40 minutes. To freeze unbaked, wrap tightly and freeze up to 2 months; thaw overnight in the refrigerator, then top and bake. If the sauce tightens after storage, stir in a splash of milk when reheating.

Nutrition (per serving)

Approximate: 710 calories; 38g protein; 66g carbohydrates; 30g fat; 17g saturated fat; 4g fiber; 830mg sodium; 6g sugars.