French Onion Soup

I made this soup for our starter at our Christmas Eve 2017 meal.  I found the recipe on Food Network.  

It says it served 4 but it easily served 5-6.

1 stick unsalted butter
6 cups thinly sliced sweet (Vidalia) onions (I sliced them ultra thin in the food processor)
Kosher salt and freshly cracked black pepper
1 tablespoon flour
1/4 cup dry sherry
5 cups beef stock
6 sprigs fresh thyme
8 slices Gruyere cheese 
2 cups coutons

Directions

In a large pot, melt the butter over medium heat.  Add the onions all at one and a small splash of water.  Season the onions with salt and pepper.  Bring the onions to a simmer, stirring often.  Reduce the heat if the onions begin to cook too fast.  Cook until the onions are soft and translucent, about 15 minutes.  (If you want a sweeter soup, continue to cook the onions until they caramelize to the richness of your preference.)

Add the flour and cook for 3 minutes.  Add the sherry and cook for a few minutes longer.  Add the beef stock and bring to a very low simmer; simmer for about 35 minutes.

Preheat the broiler to finish the soup.

Add the thyme to the soup and simmer for 5 more minutes.  Season with salt and pepper as needed.  Remove the herbs.

Ladle the soup into 4 soup crocks.  Place some croutons (recipe below) on top of the soup then cover each crock with 2 slices of cheese. 

Transfer the crocks to a baking sheet and place under the broiler until the cheese bubbles.  

Croutons:

2 tablespoons good olive oil
2 cups (1" dice) sourdough bread
Kosher salt and freshly ground black pepper

Heat the olive oil in a large (10") saute pan until hot.  Add the bread and cook over medium heat, tossing frequently, until the bread is evenly toasted and browned.  Sprinkle with salt and pepper.