Traditionally, chowder starts with butter as the fat, but you can use olive oil or bacon grease. All good chowders start with cooking aromatic vegetables.  The French have a blend of aromatic vegetables (onions, celery, and carrots), which they call mirepoix.  The Creoles have their 'holy trinity,' which consists of onions, celery, and green pepper. This corn potato chowder gets its flavor base from sauteing onions, celery, and garlic in unsalted butter.  Then fresh thyme leaves are stirred in and cooked for one minute to release more flavor. Then, the corn and potatoes are added to finish off the dish.