In a large pot, boil water and cook the spaghetti according to package instructions until al dente. Drain and set aside.
In a large skillet over medium heat, add olive oil. Sauté the chopped onion and garlic until soft, about 3-4 minutes. Then, add the sliced mushrooms and cook for an additional 5 minutes, until they begin to brown.
In a large mixing bowl, combine the sautéed vegetables, cooked turkey, frozen peas, cooked spaghetti, chicken broth, sour cream, thyme, black pepper, salt, and paprika. Stir until everything is well coated.
Pour the mixture into a greased 9x13 inch baking dish, spreading it evenly.
Sprinkle the shredded mozzarella cheese evenly over the top of the mixture.
Bake in the preheated oven for 25-30 minutes, or until the cheese is melted and bubbly.
Remove from the oven and let it sit for 5-10 minutes before serving.
Notes
Serve in individual bowls, garnished with fresh parsley or a sprinkle of additional paprika for a pop of color.