01 -  Set oven to 350°F. 
 02 -  Boil egg noodles in a large pot of salted water according to package directions until al dente. Drain and return to pot. 
 03 -  Whisk together cream of mushroom soup and milk in a mixing bowl until smooth. 
 04 -  Add drained tuna, frozen peas, and the soup mixture to the noodles. Fold gently until evenly combined. 
 05 -  Transfer mixture to a lightly greased 2-quart casserole dish. 
 06 -  Sprinkle breadcrumbs and shredded cheddar cheese evenly over the casserole if using. Bake uncovered for 20 minutes, or until hot and bubbling. 
 07 -  Allow casserole to stand for 5 minutes before portioning and serving.