Heat the butter in a large pot over medium heat. Add the onion and cook, covered, stirring now and then until softened, about 8 minutes. Add the thyme and garlic and cook a minute or two longer.

Sprinkle with flour, stirring to coat, and continue to cook for a minute or two until the flour appears dry but hasn’t picked up any color. Pour in stock, bit by bit, stirring to incorporate the flour. Bring to a good boil, add potatoes, and continue to boil for about 15 to 20 minutes, until the potatoes are soft, stirring now and then. Remove thyme sprigs.

The starchiness of the potatoes will help to thicken the soup and may be left “as is,” but if you’d like a chowder with more body, after the boil, remove the potatoes and stock to a blender and blend, being careful of the hot liquid. Alternatively, the potatoes could be blended with a stick blender or mashed by hand right in the pot.

While the potatoes are boiling, remove the corn from the cob using a sharp knife (cut over an inverted bundt pan or large cookie sheet to capture the kernels). When the potatoes are cooked (or cooked and blended), add the corn. Bring back to a simmer and cook until corn is desired doneness, three to four minutes, stirring often.

Remove from heat and add cream or half and half. Add salt and pepper to taste. Ladle into bowls and sprinkle with parsley.

Note: For a little more flavor, reserve the cobs and break them into two pieces. Add to the soup with the potatoes, then before adding the corn, remove the cobs and scrape them with the back of a knife to “milk” them. Hold them over an inverted bundt pan using a corn cob holder. Add the resulting liquid back into the soup.