Preheat oven to 350°.
Cook corn in boiling salted water 2 or 3 minutes.
Drain and combine with milk, egg, onion, salt, pepper and Swiss cheese.
Place in greased 10 x 6-inch casserole.
Toss cracker crumbs with butter.
Sprinkle over corn mixture.
Bake 30 to 35 minutes.
Let set a few minutes before serving.