Step 1

Melt butter with olive oil in a Dutch oven or heavy bottom stock pot. Add the onions, brown sugar, salt and pepper. Increase heat to medium high and cook for 5 minutes, stirring often.

Step 2

Reduce heat to medium and cook onions, stirring frequently (especially towards the end so they don’t burn), scraping the bottom and sides of the pan, until they are deeply browned, 40-50 minutes. Turn heat down if the onions scorch or stick to the pan (I turn heat down the last 15 minutes).

Step 3

Add garlic and cook for 30 seconds over medium heat. Add water, balsamic vinegar, soy sauce and Worcestershire sauce and stir to scrape up any browned bits on the bottom of the pan. Cook until liquid is absorbed.

Step 4

Sprinkle flour over onions and cook while stirring for 2 minutes.

Step 5

Add the beef broth, bay leaves, thyme, ¼ teaspoon salt, ¼ teaspoon pepper and all seasonings.

Step 6

Bring soup to a boil then reduce to a gentle simmer. Simmer uncovered on LOW for 20 minutes, stirring occasionally.

Step 7

When ready to eat, toast bread by spreading slices in an even layer on a baking sheet. Broil on the middle rack of the oven until golden, 5-7 minutes. Flip over and broil another 3 minutes or until golden. Sprinkle bread with Gruyere and broil on the middle rack until cheese melts, 3-5 minutes.

Step 8

Ladle soup into bowls and top with 1-2 cheesy crouton slices (depending on if you used a loaf or baguette).

Step 9

Alternative method for OVEN SAFE bowls: Ladle soup into bowls, top with a slice of bread then cheese. Place bowls in the oven on the middle rack and broil 3-5 minutes or until cheese is melted.