In a large nonstick skillet, melt the butter over medium heat. Add the onion and thyme and saute about 4 minutes, or until the onion is tender and very pale golden. Stir in the corn, then stir in the cream and milk. Bring to a simmer and simmer 3 to 5 minutes, or until the corn is heated through but still crisp-tender.
Season the corn to taste with salt and pepper. Discard the thyme stems and serve immediately.