Soupe à l’Oignon Gratinée
French Onion Soup
Few dishes encapsulate comfort and elegance quite like French onion soup. This rich, savory broth, brimming with caramelized onions and crowned with a golden, bubbly layer of cheese, has captivated food lovers for centuries. A staple in French cuisine, its origins are humble, yet its depth of flavor and satisfying warmth make it a beloved dish across the globe.
French onion soup dates back to at least the 17th century, though some variations can be traced to Roman times. Originally a dish for the working class, it was made using simple, inexpensive ingredients: onions, bread, and broth. Over time, it evolved into a refined culinary treasure, finding its place in Parisian cafés and fine dining establishments alike. Today, it remains a cherished part of French gastronomy and an enduring comfort food worldwide.
The soul of French onion soup lies in its deeply caramelized onions. Achieving this rich flavor requires patience, as onions must be cooked slowly over low heat until they develop a deep golden brown hue. This process can take much more than an hour, but the result is an intensely sweet and savory base that defines the soup’s character.
French Onion Soup Recipe
Ingredients
- 4 T. unsalted butter
- 1 t. sugar
- 2 1/2 lbs. yellow onions, thinly sliced
- 4 garlic cloves, minced
- 2 t. sea salt
- 1 t. freshly ground black pepper
- 2 t. flour
- 3/4 c. sherry
- 1 qt. chicken bone broth
- 1 qt. beef bone broth
- 1 T. high-quality balsamic vinegar
Method
Melt butter in a large pan or Dutch oven medium heat. Add sugar, stir, then add onions and toss to coat. Cook for about 20 minutes, stirring occasionally, until the onions become soft.
Stir in garlic, salt, and pepper. Lower heat to very low and cook until the onions are deeply caramelized but taking extra care not to burn. About 1 1/2 hours or more. Stir occasionally only.
Sprinkle flour over the caramelized onions, raise heat to medium and stir to cook the flour, about 2 minutes. Add the sherry to deglaze, scraping up any onion or brown bits that may have stuck to the pan. Then allow the sherry to reduce for a few minutes before adding the broth. This helps cook off the alcohol while concentrating the flavor, enhancing the soup’s depth without an overpowering boozy taste.
Add the broths and bring the soup to a boil. Lower the heat then simmer for an additional 45 minutes.
Remove the soup from the heat. Add balsamic vinegar. Taste for more salt and pepper if needed.
To Plate
- sliced baguette, about 3/4″ slices
- whole garlic cloves, peeled
- grated gruyere cheese, 3 cups or more
Toast the baguette slices. Rub both sides of the toast with a raw clove of garlic.
Place ovenproof soup bowls on a parchment lined baking sheet. Ladle onion soup into bowls. Arrange toasted baguette slices on top of the soup. Cover the toasts with generous amounts of grated gruyere.
Place the baking sheet on an upper rack in a 400°F oven until the cheese melts and turns golden and bubbly. Serve immediately.
Notes
Whether enjoyed in a Parisian bistro or homemade in a cozy kitchen, French onion soup remains a culinary treasure!
The quality of the broth is crucial in French onion soup, as it forms the backbone of the dish. A rich, well-made broth enhances the depth of flavor and complements the sweetness of the caramelized onions. Homemade broth is often ideal, but here I use my favorite store-bought soups, a combination of Zoup Beef Bone Broth and Chicken Bone Broths for their delicious complex flavors. Their motto is “Good Enough to Drink.” And it is!
The flavor of this rich soup is heightened by the sherry. Oloroso Sherry from Jerez, Spain has wonderful aromas of nuts, vanilla and caramel plus rich nutty semi-sweet creamy flavors. Oloroso sherries offer a terrific balance between sweet and dry. Serve a glass on the side to accompany the soup and a green salad!
A special merci beaucoup to my dear friend Liz for the charming L’Amour Toujours salad plates by Juliska. Love Forever! ❤️
This recipe was inspired by le magnifique livre de cuisine My Paris Kitchen by David Lebovitz, another truly appreciated French-style gift from Don & Kristy. ❤️
