Make French onion soup

French onion soup is very little food: onions, broth, bread, cheese. The depth comes from time. This is how to make French onion soup that tastes like it came from a bistro, and the honest answer is that it takes about two hours, though most of it is stirring now and then. Choose a night with nowhere to be.

Before you start

• Plan for about 2 hours in all. The onions alone need 45 minutes to an hour.
• Use a heavy pot, ideally with a wide base. A thin pot scorches the onions.
• You’ll finish the soup under the broiler, so use bowls that are labelled oven-safe or broiler-safe. Ordinary bowls can crack. If yours aren’t, toast the bread and cheese on a baking sheet and float them on top.

What to use

For 4 bowls:

• 4 large yellow onions (about 2 pounds), thinly sliced
• 3 tablespoons butter, plus a little oil
• 1 teaspoon salt
• 2 cloves garlic, minced
• 1 tablespoon flour
• 6 cups beef or vegetable broth
• A few sprigs of thyme and a bay leaf
• Optional: a splash of dry white wine or sherry (adults only, and 21 and over in the US)
• 4 thick slices of crusty bread
• About 1½ cups grated Gruyère

How to make French onion soup

1. Slice. Cut the onions in half through the root, peel them, and slice thinly from end to end. Even slices cook evenly. A sharp knife helps with the stinging eyes.
2. Start them. Melt the butter with the oil in the pot over medium heat. Add the onions and the salt. They will fill the pot, then shrink.
3. Cook low and slow. Turn the heat to medium-low. Stir every few minutes for 45 minutes to an hour. They go limp, then pale gold, then amber, then deep brown. If they stick, add a splash of water and scrape the bottom.
4. Add garlic and flour. Stir in the garlic for 30 seconds, then the flour for a minute.
5. Deglaze. If you’re using wine, pour it in and scrape up the brown bits. Let it cook down.
6. Simmer. Add the broth, thyme and bay leaf. Simmer, partly covered, for 30 minutes. Taste, and add salt and pepper. Remove the bay leaf and thyme stems.
7. Toast the bread. Toast the slices in the oven until dry and crisp.
8. Finish. Heat the broiler. Ladle soup into oven-safe bowls on a baking sheet, top each with toast and a generous pile of Gruyère. Broil a few minutes, watching closely, until the cheese bubbles and browns.

Let the bowls cool a few minutes before you eat. The bowls, the cheese and the soup underneath are all very hot.

Why it takes so long

Onions are mostly water. Over low heat the water cooks off, the natural sugars brown, and the onions shrink to a fraction of what you started with. Four large onions end up as barely a cupful of dark, sticky strands. Turning up the heat to save time just scorches the edges while the middle stays raw, so use the hour for something else and come back to stir. A wide pot speeds it up, because the water escapes faster.

What goes wrong

• The onions burn. The heat is too high. Turn it down and add a splash of water. If they’ve turned black or bitter, start again.
• The soup tastes thin. The onions weren’t browned enough, or the broth is weak. Cook them longer next time, and use a good broth.
• It tastes too sweet. Add a splash of vinegar or a little more salt.
• The cheese won’t melt right. Grate it yourself instead of using pre-shredded, and move the bowls closer to the broiler.
• The bread turns to mush. Toast it hard first, so it holds.

After

The soup itself keeps in the fridge for several days and tastes better the next day. Store it without the bread and cheese, and add those fresh when you reheat. It also freezes well.

Make it a winter evening

Put it on when you get home on a dark afternoon, and let the kitchen smell like it while you do something else between stirs. It goes well with a long classic novel, or a loaf you baked yourself from the bread idea.