Favourite French Onion Soup

The whole soul of French onion soup is in how far you take the onions. Cooking them only until clear gets you a watery soup. Pushing them to deep, sweet golden brown is what gives the broth its caramel-edged backbone.

This quick version uses chicken stock instead of the traditional beef bone broth, which lightens the soup and lets the onion flavor sit out front. Thyme and bay quietly underpin everything.

The Gruyere cap is non-negotiable. Its nutty, slightly sharp melt is what makes the soup unmistakable. Mozzarella, Swiss, or generic shredded blends never get the same depth.

The broiler stage is fast and unforgiving. Watch the bowls the entire time, since cheese moves from glossy to bubbly to scorched in under a minute. Pull when the surface is dappled with deep brown spots.

Pro Tips

• Slice the onions thin and uniformly. Even cuts caramelize at the same rate.
• Use a wide, heavy-bottomed pan and resist stirring constantly. Letting the onions sit lets fond build, which is the brown flavor at the bottom of the pan.
• Stale French bread toasts better than fresh. The drier crumb soaks up broth without dissolving.
• Use oven-safe bowls or a hot ramekin. Cold bowls crack under the broiler.

Variations

• Deglaze the onions with a splash of dry white wine or brandy before adding stock for extra depth.
• Add a teaspoon of balsamic vinegar at the end for a tangy lift.
• Use beef bone broth for a more traditional, robust version.