Creamy Macaroni and Cheese

1 3/4 cups elbow macaroni, uncooked
2 cups small-curd cottage cheese
2 cups shredded Cheddar cheese
1 8 oz. container sour cream
3 tablespoons finely chopped onions
1 egg, beaten
3/4 teaspoon salt
1/4 cup soft bread crumbs
1 1/2 tablespoons butter or margarine, melted

Cook macaroni according to package directions;
drain. Combine macaroni and next 6 ingredients,
stirring well. Spoon mixture into a greased 2-quart
casserole. Combine breadcrumbs and butter, stirring
well. Sprinkle breadcrumb mixture evenly over casserole.
Bake uncovered at 350 degrees for 45 minutes or
until heated through.