Cook egg noodles according to package directions; drain. Meanwhile, in a large bowl combine the ham, soup, 2 cups cheese, sour cream, onion, green peas and butter. Add the pasta; toss to coat.

Transfer to a greased 13x9-in. baking dish. Cover and bake at 350° for 35 minutes. Uncover; sprinkle with remaining cheese. Bake 15-20 minutes longer or until cheese is melted. Makes 8 servings.