Costco French Onion Soup Recipe
Costco French Onion Soup is super popular, and it’s easy to see why. It’s made with caramelized onions and topped with melted Gruyère cheese which makes it both tasty and fancy. You can find it in the freezer section under the Cuisine Adventures brand. It’s quick and easy to prepare, perfect for when you’re craving a warm, delicious soup.
Equipment
- Large Dutch oven or heavy-bottomed pot for caramelizing onions.
- Wooden spoon for stirring
- Baking sheet for toasting baguette slices.
- Oven-safe bowls to assemble the final dish.
- Cheese grater or food processor for shredding Gruyère.
Ingredients
Soup Base:
- 4 large yellow onions about 2 lbs
- 4 tbsp unsalted butter
- 1 tbsp olive oil
- 2 cloves garlic minced
- 1 tsp sugar optional, to enhance caramelization
- 6 cups beef broth or substitute with vegetable broth for a vegetarian option
- 1/2 cup dry white wine optional, for added depth
- 1 bay leaf
- 1 tsp dried thyme
- Salt and pepper to taste
Toppings:
- 1 baguette sliced into 1-inch rounds
- 2 cups grated Gruyère cheese or a mix of Gruyère and Parmesan
- Optional extras like fresh parsley or chives for garnish
Instructions
Step 1: Prepare the Onions
- Start by peeling and thinly slicing a large quantity of yellow onions. For a rich and flavorful soup, you’ll need about 4-5 onions. Heat butter and a drizzle of olive oil in your large Dutch oven or heavy-bottomed pot over medium heat. Add the sliced onions and a pinch of salt, then cook slowly, stirring occasionally. Let them caramelize for 30-40 minutes until they turn deep golden brown and develop a sweet, rich flavor.
Step 2: Deglaze the Pot
- Once your onions are caramelized, pour in some dry white wine or sherry. Use a wooden spoon to scrape up the browned bits from the pot. This adds extra flavor to the soup. Let it cook for a few minutes until the alcohol evaporates, leaving a nice aroma and taste.
Step 3: Add Broth and Simmer
- Pour in your beef or vegetable broth, making sure to cover the onions completely. For authentic French Onion Soup, beef broth is traditionally preferred for its rich and hearty flavor. Add aromatic ingredients like a sprig of thyme and a bay leaf to elevate the flavor. Bring the soup to a gentle boil, then lower the heat to let it simmer. Allow it to cook for 30 minutes so the flavors mix nicely.
Step 4: Prepare the Baguette Slices
- While the soup is cooking, heat your oven to 375°F (190°C). Cut a baguette into slices and put them on a baking tray. Toast them in the oven for 5-7 minutes until they are firm and slightly golden. This will help the bread hold together in the soup.
Step 5: Assemble and Broil
- Once your soup is ready, ladle it into oven-safe bowls. Place one or two toasted baguette slices on top of each bowl of soup. Generously sprinkle shredded Gruyère cheese over the baguette, covering the surface. Place the bowls on a baking tray and put them in the oven on broil. Broil for 2-4 minutes until the cheese is melted, bubbly, and lightly browned. Watch carefully so it doesn’t burn.
Step 6: Serve and Enjoy
- Carefully remove the hot bowls from the oven and allow them to cool slightly. Garnish with a sprinkle of freshly chopped parsley for a touch of color and freshness. Serve the soup quickly while the cheese is gooey and the flavors are at their peak.
Notes
When making French onion soup, ensure to caramelize the onions slowly for that deep, sweet flavor—don’t rush this step! It’s also best to use high-quality cheese and fresh bread for the topping to elevate the dish. A little patience and attention to detail make all the difference in achieving a rich, authentic taste.