Instructions

1. Preheat the oven to 350°F. Grease a 9x13 baking dish, set aside. Cook the spaghetti per the directions on the back of the box, drain and set aside.
2. In a large skillet with deep sides, add 6 tablespoons of butter over medium-low heat. Once melted, add in the onions and cook until translucent, about 5 minutes, stirring occasionally. Add in the garlic and stir until fragrant, about 30 seconds. Add in the mushrooms, thyme, and rosemary. Cook, stirring occasionally until the mushrooms are softened, about 5 minutes.
3. Add the flour and stir together to coat, cook for 2 minutes, stirring occasionally. Slowly add in the chicken stock, stirring constantly so no lumps form. Add in the half & half slowly, stirring constantly. Whisk everything together to make sure there are no lumps of flour. Bring to a simmer and simmer about 3 minutes, until thickened.
4. Stir in the sour cream until combined. Add the salt, pepper, half of the parmesan cheese, the turkey, and the peas. Stir to combine fully.
5. Add in the spaghetti noodles and coat in the sauce. This might be tricky, I like to use a pair of tongs for this. Pour everything into the prepared baking dish. 
6. Melt the remaining 2 tablespoons of butter. Stir the butter with the crushed crackers and the remaining ¼ cup of parmesan cheese. Evenly distribute the mixture on top of the casserole. Bake for 25-30 minutes until hot and the crust is a golden brown. Let cool slightly and serve.