If using fresh corn, with a sharp knife cut corn from cobs about two-thirds down the kernels; do not scrape cob. (You should have about 1-1/2 cups of corn.) Add the fresh or frozen corn, water, onion, and pepper to the saucepan. Bring just to boiling. Reduce heat. Cover and simmer for 5 to 7 minutes or until corn is crisp-tender.