A simple way to prepare this cheesy and delicious soup.
In a medium saucepan, sauté onions in oil and butter for 15–20 minutes, stirring frequently, until they caramelize. Add all of the remaining ingredients, except the croutons and cheese; cover pan and simmer soup for 20 minutes while flavors meld.
To serve, drop 3–4 seasoned croutons into the bottom of each bowl. Ladle soup over the croutons and top with cheese.