Grate corn or split kernels with a corn scraper or sharp knife.
Hold cobs over a bowl and scrape off kernels with back of knife.
Add remaining ingredients except egg whites and beat well to blend.
Fold in whites.
Pour into greased 9-inch casserole or baking dish and put in shallow pan of water in preheated moderate oven (375°F.) Cook until the mixture just sets, 50 to 60 minutes.