1-First Step: Prepare the pasta and mise en place Boil 12 oz spaghetti in salted water until al dente, about 8-10 minutes. Drain and set aside. Meanwhile, shred 3 cups cooked chicken and grate 1 cup Parmesan. Slice 8 oz mushrooms and mince 2 garlic cloves. Grease a 9×13-inch baking dish. This setup keeps things smooth.

2-Second Step: Sauté the mushrooms and garlic Heat 2 tbsp butter in a large skillet over medium heat. Add mushrooms and garlic, cooking for 5 minutes until softened and golden. Stir occasionally to avoid burning. For gluten-free, this step stays the same. Remove from heat and set aside.

3-Third Step: Make the creamy sauce In the same skillet, melt 4 tbsp butter over medium heat. Whisk in 1/4 cup flour, stirring for 1-2 minutes to form a roux. Gradually pour in 2 cups chicken broth, whisking constantly to prevent lumps. Add 1 cup cream and 1/2 cup sherry. Simmer 5-7 minutes until thickened. For low-calorie, use milk here. Stir in 1 cup Parmesan until melted.

4-Fourth Step: Combine all ingredients Add cooked spaghetti, shredded chicken, sautéed mushrooms, and 1/2 cup peas to the sauce. Toss gently to coat evenly. Taste and adjust salt or pepper. Vegan adaptation: use plant-based alternatives now. Transfer mixture to the prepared baking dish.

5-Fifth Step: Prepare and add the topping Mix 1/2 cup breadcrumbs with 2 tbsp melted butter and extra grated Parmesan. Sprinkle evenly over the casserole. This adds the signature crunch to your chicken tetrazzini with spaghetti.

6-Final Step: Bake and serve Preheat oven to 375°F. Bake for 25-30 minutes until bubbly, hot, and topping is golden brown. Let rest 5 minutes before serving. Garnish with fresh parsley if desired. Slice into portions for a quick chicken tetrazzini dinner. Pairs well with a green salad.