You can make this ahead, cool, cover, and refrigerate, but be sure to make extra sauce so it won't be dry.
Preheat oven to 350
3 tbl butter
2 cups more or less cooked, cubed turkey or chicken
2 celery stalks, diced
1 carrot, peeled and diced
1/2-1 cup sliced mushrooms
1/2 small onion, chopped fine or 1-2 green onions, chopped
1 garlic clove minced
6 tbl flour
1/2 cup white wine
2 1/2 cups chicken stock
2 cups sharp cheddar cheese, shredded, or 1 cup parmigiano reggiano, or a combo
1/4 tsp cayenne pepper
Salt and black pepper to taste
1 tbl worcestershire
1/2 lb spaghetti, broken, cooked, and drained
Panko bread crumbs, tossed with a little olive oil or melted butter to top casserole.
Melt the butter in a sauce pan and add all the vegetables and a pinch of salt and pepper, sauteing until onion is translucent. Add flour and cook for 2-3 minutes. Add wine and stock, slowly, whisking. Bring to a boil. Remove from heat and add cheese, salt, peppers, worcestershire sauce. Stir, taste, and correct seasonings. Stir in turkey and spaghetti; pour into greased oven-proof casserole dish. Top with bread crumbs and bake 30-45 minutes until browned and bubbly. If you have refrigerated the casserole beforehand, cover and bake for 30 minutes, remove cover and bake another 30 minutes.