Use a large bowl to catch all the kernels and juice from the cobs. Using a very sharp paring knife cut the very tips of the kernels off the cob. Then use a fork to scrape what remains of the kernels plus all the juice.
Transfer to a saucepan and add the milk, butter, salt. and pepper and heat over medium - medium low heat stirring constantly. Cook for 10 minutes. If it's a little watery add the corn starch to thicken and cook an additional 5 minutes.