Gather the ingredients and preheat oven to 350 F.
Grease a 2-quart baking dish.
Cook pasta (you can use mini fusilli or farfalle, macaroni, or other shapes) in boiling salted water following package directions. Drain, rinse and set aside.
Heat butter in a large skillet and saute the onion and celery over medium-low heat until softened.
Add ham and stir in flour until well combined.
Gradually stir in the milk until thickened. Add marjoram, salt, and pepper. Stir in the cheese, turkey, and peas and carrots, if using.
Add the cooked pasta and blend thoroughly. Spoon the pasta mixture into the prepared baking dish.
Combine breadcrumbs with 1 tablespoon melted butter; sprinkle over the top of the casserole.
Bake for 25 to 30 minutes, until bubbly and the topping is browned.
Serve and enjoy!