Melt butter in a skillet over medium-low heat, add flour and milk to make rue. Stir in the onion, celery, and garlic, and condensed soup. Continue to cook and stir 5 minutes. Might need a little more milk.
Season with salt and pepper. Stir in tuna, peas,half of cheese then cooked noodles. Transfer to the baking dish. Top with remaining cheese and sprinkle with bread crumbs.
Bake 25 minutes in the preheated oven, or until bubbly and lightly browned.