Cook noodles according to package instructions, rinse with cold water and set aside.
In a small bowl, combine the crushed crackers with ¼ cup parmesan cheese, and 2 tablespoons melted butter. Mix and set aside. That’s the buttered crumbs topping.
In a skillet, melt 2 tablespoons of butter, sauté onion until soft and translucent. Add mushrooms, season with salt and pepper and cook for 4-5 minutes or until softened.
Add flour, and cook for 1 minute. Pour stock over the flour, whisk and bring to a boil.
Reduce to a simmer, cook for a few minutes to thicken then stir in the cheddar cheese and ¼ cup of parmesan. Add the turkey, and peas. Stir in the lemon juice and season with salt and pepper. Stir so that everything is well combined (if using a different dish to bake in, transfer to the baking dish). I used a Le Creuset 11 inch shallow casserole dish, it’s 3 ½ qt. 9x13 dish can also be used.
Top with the buttered crumbs, and bake for 20 minutes.
Notes
Pasta. Al dente pasta (with some bite to it) is best for casseroles, since the noodles will cook more during baking. Be sure to rinse them after cooking so that they don’t continue to cook while waiting to be added to the sauce.
Storing. Store leftover turkey casserole in the fridge, covered, for up to 4 days. Reheat in the microwave.