Done correctly, French onion soup is very pleasing. The beefy broth and sweet onion flavors can’t be beat. Served gratinéed, it makes a nice lighter meal as opposed to a starter as it is often presented in restaurants.
I’ve had some excellent French onion soups, but I have also had a few that were less than exceptional. The difference can typically be traced back to the broth and how the onions were cooked. A good – preferably home made – beef broth should always be the base. Secondly, French onion soup takes time. The onions need to be cooked slowly over low heat so they have a chance to caramelize yet not burn. It will take 30 to 45 minutes for this to happen, but your patience will be rewarded.
Start over low heat and slowly sweat the onions along with a couple sprigs of thyme and bay leaves. Generously season them with salt and pepper. I like to use a variety of onions including red, yellow, and white. They each bring subtle differences in flavor to the party.
The onions will begin to caramelize after about 30 minutes. Continue cooking until the onions become very brown.
Add red wine, bring to a boil, and then reduce reduce heat to a simmer and cook until all the wine is cooked out.
The onions will once again look somewhat dry.
Turn the heat to low, dust the onions with flour and cook for about five minutes or until the flour takes on a nutty aroma. You don’t want a flour taste in your soup.
Remove the thyme sprigs and bay leaves before adding the broth. Bring back to a simmer and cook for another ten minutes. Ladle the soup into heat proof bowls, top with a slice or two of baguette and Gruyère cheese. Place the soup under a broiler and broil until the cheese is melted and just begins to brown. Serve immediately.
French Onion Soup
1/2 cup unsalted butter
3 onions, sliced
3 garlic cloves, chopped
2 bay leaves
2 fresh thyme sprigs
Kosher salt and freshly ground black pepper
1 cup red wine
3 heaping tablespoons all-purpose flour
4 cups beef broth
1 baguette, sliced
1/4 pound grated Gruyere
Melt the butter in a large pot over medium heat. Add the onions, garlic, bay leaves, thyme, and salt and pepper and cook until the onions are very soft and caramelized, about 30 to 45 minutes.
Add the wine and bring to a boil. Reduce the heat and simmer until the wine has cooked down and the onions are somewhat dry.
Discard the bay leaves and thyme sprigs. Dust the onions with the flour and give them a stir. Turn the heat down to medium low so the flour doesn’t burn and cook until the flour takes on a nutty aroma and loses the raw flour taste; about 10 minutes.
Now add the beef broth and bring the soup back to a simmer. Cook for about another 10 minutes and season to taste with salt and pepper.
A few minutes prior to serving, preheat the broiler. Slice the baguette into 3/4 to 1″ thick slices and lightly toast both sides of the baguette under the broiler. Then, ladle the soup into oven proof bowls and float a slice or two of toasted baguette on top of the soup. Top the baguette with Gruyère and broil until bubbly and golden brown; 3 to 5 minutes. Serve immediately.