Buttery noodles, creamy cheese, sweet green peas, and savory ham come together in this cozy baked ham tetrazzini with spaghetti, mushrooms, and cheddar. Bubbly, creamy, and slightly crisp on top—this is weeknight comfort food that wraps around you like a warm blanket.
Bring a large pot of salted water to a boil. Cook the spaghetti until just al dente. Reserve 1/2 cup of pasta water (optional), then drain and set aside.
In a large skillet over medium heat, melt 2 tablespoons of butter. Add onion and mushrooms, and sauté for about 5–6 minutes, until softened. Stir in the garlic and cook for 1 minute more, just until fragrant.
Add the remaining 1 tablespoon butter to the pan. Once melted, sprinkle in the flour. Stir constantly for 1–2 minutes until a golden paste forms.
Gradually whisk in the milk and then the chicken broth, ensuring the mixture stays smooth. Stir in thyme. Simmer for 3–4 minutes, stirring, until the sauce thickens but is still pourable.
Turn heat to low. Add shredded cheddar cheese and stir until fully melted and the sauce is creamy. Fold in the diced ham and thawed peas. Season generously with salt and black pepper, tasting as you go.
Add the cooked spaghetti to the pan and gently toss until evenly coated in sauce. If the mixture seems too thick, add a splash of reserved pasta water to loosen.
If desired, transfer to a greased 9x13-inch baking dish. Sprinkle Parmesan evenly on top. Broil for 2–3 minutes or until bubbly, golden, and crisp at the edges.
Let rest for 5 minutes, then sprinkle with fresh parsley. Serve warm, straight from the skillet or baking dish.
Notes
This recipe is endlessly customizable: swap peas for broccoli, use a different pasta shape, or try turkey or chicken instead of ham. To make ahead, assemble up to a day in advance and refrigerate. Bake until hot and bubbly, adding 5–10 minutes to the bake time if cold.For leftovers, store in an airtight container in the fridge for 3–4 days. To reheat, add a splash of milk or broth if needed.