King Louis XV’s Soupe à L'oignon Gratinée

Although the onion dates back to 3500 BC, legend has it that French onion soup was first made by King Louis XV of France, in the 1700’s. One night, with only onions, butter and champagne available in his sparse kitchen at the hunting lodge, he experimented with making a ‘stew’. Without King Louis’ hunger pang I wonder how long we would have waited before someone else invented this spectacular concoction!

Onion soup has actually been referred to as peasant food because onions have always been so cheap and widely available. It wasn’t typically made with champagne though! Water would have been used for the broth.

The dish regained popularity in North America in the 1960’s with the exploding interest in French cuisine. Probably due in part to the influence of American chef, author and television personality, Julia Child. It is said that she had French onion soup at her last meal before she died.

One of the most important steps in making French onion soup is to create a 'fond'. This is the brown bits on the bottom of the pot that forms when the sugars in the onions break down as they caramelize.

I like King Louis XV’s luxurious contribution to this French classic and so when I made my most recent batch at the beginning of this week, I reached for the bubbly! He was right. Definitely a soup fit for a king.

Here is my take on the french classic.

King Louis XV’s Soupe à L'oignon Gratinée
Adapted from recipes by King Louis XV of France, Julia Child, Cook's Illustrated and just about every other 'expert' on French Onion Soup over the past 300+ years.

Serves 6.

8 cups of sliced yellow onions
¼ cup unsalted butter
3 cloves minced garlic
1 teaspoon sugar
1 teaspoon salt
3 tablespoons all-purpose flour
1 ½ cup champagne or prosecco
7 cups beef broth
1 bay leaf
5 sprigs of thyme
salt and pepper to taste
baguette slices, ½-inch thick
2 cups grated Gruyère cheese (approx. 4 tablespoons per bowl)
6 tablespoons grated Parmigiano-Reggiano cheese (approx. 1 tablespoon per bowl)
6 tablespoons Mozzarella cheese (approx. 1 tablespoon per bowl)

Cut onions in half length-wise and then thinly slice each half. Melt butter in a heavy bottomed Dutch oven. Add onions and garlic and cook over medium heat, stirring occasionally for about 20 minutes. This process is called ‘sweating’. It is key to release the onion’s excess moisture before beginning the caramelization process.

Stir in sugar and salt. Cook slowly stirring frequently, until onions are a deep, rich caramel brown. This can take at least an hour for complex aromatic flavours. As the ‘fond’ forms on the bottom of the pot, watch that the onions do not over caramelize. You can add some water to deglaze and even out the colour as you continue to strive for a deep dark brown. You may find that you need to adjust the heat up and down as you work this part of the process.



Add the flour and stir. Cook for a few minutes so the flour is no longer raw.

Add in your champagne (or prosecco) and bring to a boil. Then add your beef broth, bay leaf, and sprigs of fresh thyme. Simmer covered for about 30 minutes. Remove the bay leaf and the 5 thyme sprig twigs.

Taste, and adjust the salt and pepper accordingly.

Baguette slices can be toasted at 400ºF for 10 minutes to make them dry, crisp and lightly brown.

Ladle soup into French onion soup bowls (or oven-proof bowls). Cover surface area with baguette slices. Cover toasts with Gruyère, mozzarella, and Parmigiano-Reggiano cheeses. Place under broiler until cheese has melted and is lightly browned.



TIPS:
Letting the soup broth sit for a day allows the flavours to mature together.

If you do not have homemade beef stock, consider the beef stock made at the Glebe Meat Market on Bank Street. If you do use the beef stock in the tetrapak, reach for low-sodium.

The soup broth does freeze well.