This is the best French onion soup recipe. Often I’m experimenting with new recipes, but this is one dish that I stick with what I know is awesome. It does take a commitment to caramelize the onions slowly, but most of the time is hands-off, just a way to make your kitchen smell amazing while you wait.
If you don’t want to stir the onions on your stovetop, you can easily caramelize the onions in a slow cooker.
What Type of Onions Should You Use?
This recipe is all about the onions! I like to use yellow onions for the base flavor, vidalia onions (sweet onions) for a touch of sweetness, red onions for color, shallots for a hint of garlic. Yes, that is four types of onions, they combine to give the full spectrum of onion flavor. And to take the flavor over the top, we are going to caramelize them so they have maximum flavor.
Caramelized Onions Are The Secret to the Best French Onion Soup
There is no speedy solution to get the onions to properly caramelize. It takes time, lots of time, about 2-3 hours to get the onions a nice lovely brown. (An added bonus is your kitchen will smell amazing the whole time the onions are cooking.
Remove the paper from the onions and slice them from root to blossom end into 1/4” slices, cut them thick enough that they won’t become stringy when they are cooked down. (Do the same treatment with the shallot.) It will seem like a huge pile of onions, but the slices will melt down to less than a quarter of volume as they cook. Remember onions are 80% water, all the water in the onion slices will need to be cooked out before the onions can start to caramelize.
Melt the butter and add the olive oil to a large saucepan over medium heat. Add the onion slices and toss to coat with the oil. Then just let them cook. Once they turn translucent, reduce the heat to low and open a good book. You will want to stir the onions about every 15 minutes. For the 90 minutes, the onions will stubbornly stay light in color, but don’t get impatient and turn up the heat, just let them simmer. After a while, your patience will be rewarded, with the most amazing golden brown onions that taste like heaven.
To caramelize onions in a slow cooker.
Add the butter (melted) and olive oil to the slow cooker and stir all the onions to coat with oil. Put on the lid and cook on low for 10-12 hours. They will be golden brown, sweet and caramelized perfectly.
Once the onions are caramelized, the soup comes together quickly and can simmer for 45 minutes. Just enough time to make a salad, slice the baguettes and shred the cheese. Just before serving, melt the cheese over the baguette slices. Dish up the soup and top each bowl with a cheesy toast. Dinner is served. Trust me, this best French onion soup is worth the time.
Cheese and Wine
I like to use a combination of Gruyere and Swiss or Provolone cheese. To get the cheese mixture, just shred each cheese and toss them together. Sprinkle the combo onto the baguette slices and toast in a 400°F oven until the cheese is bubbly.
You can use a dry white wine (Sauvignon Blanc, Pinot Grigio, or dry sherry) to deglaze the pan and start the soup base. You don’t want to cook with alcohol, substitute by mixing 1/4 cup red wine vinegar, 1 teaspoon brown sugar, and 1/2 cup warm water together and stir well to combine.Print
What is more comforting than the best French Onion Soup simmering in your kitchen for dinner. It takes a couple of hours of hand-off time but is so worth it.
- 3 yellow onions, sliced into 1/4” slices
- 2 Vidalia onions (sweet onions), sliced into 1/4” slices
- 1 red onion, sliced into 1/4” slices
- 1 large shallot, sliced into 1/4” slices
- 3 tablespoons butter, melted if cooking onions in the slow cooker
- 2 tablespoons olive oil
- 3/4 cup dry white wine, or 1/4 cup red wine vinegar, 1 teaspoon brown sugar and 1/2 cup warm water.
- 2 garlic cloves, minced
- 2 tablespoons tomato paste
- 1 teaspoon cocoa powder
- 6 cups beef bone broth
- 4 cups chicken broth
- 1 bay leaf
- Kosher salt and pepper to taste
- 1 teaspoon fresh thyme, stem removed
- 1/2 baguette, cut into 3/4” slices
- 1 cup gruyere cheese, shredded
- 1 cup provolone cheese, shredded (or Swiss cheese)
- Peel and slice onions and shallots.
- In a large saucepan over medium heat, melt the butter and add the olive oil. Stir in the onions and shallots and using tongs, toss to coat with oil.
- Saute onions until translucent and then reduce heat to low and simmer until golden brown and caramelized, about 2-3 hours, stirring occasionally to keep the onion edges from browning before the onions have caramelized.
- If cooking in a slow cooker, melt the butter and stir in the olive oil. Toss the onions to coat and cook on low for 10-12 hours.
- When the onions have cooked, (in a slow cooker), transfer the onions, any liquid in the slow cooker, and 1 tablespoon addition butter to a large saucepan and heat over medium heat to cook off the liquid and melt the butter.
- Add the wine or substitute to the saucepan to deglaze the pan. Increase the heat to medium-high and bring to a boil until the liquid has evaporated.
- Add the minced garlic, tomato paste and cocoa powder and stir to combine with the onion slices.
- Stir in the beef bone broth and chicken broth and bring to a simmer. Stir well and add the bay leaf. Simmer for 45 minutes.
- Remove the bay leaf, and discard. Taste and season with kosher salt and pepper.
- While the soup is simmering, preheat the oven to 400°F.
- Slice the baguette and shred the cheese.
- On a baking sheet, arrange the baguette slices and sprinkle the combination of cheeses over each slice of bread.
- Add the pan to the oven and cook until the cheese is bubbly and bread is toasted, about 6 -8 minutes.
- Remove the baking pan from the oven when the cheese is bubbly.
- Ladle to onion soup into bowls. Sprinkle the fresh thyme on the soup and top each bowl with a sprinkle of shredded cheese and then carefully place a cheesy baguette toast on top. Serve immediately.