Four-Onion Soup

Classic French onion soup uses one type of onion. This version uses four: yellow onion for sweetness, red onion for sharper bite, leeks for mellow depth, and scallions for a fresh, grassy note. Each brings a different flavor to the broth, creating a more layered and complex soup than any single onion could.

All four get sliced to the same quarter-inch thickness and sauteed gently in butter with garlic for 15 minutes until golden and soft. A pinch of nutmeg adds a warm, unexpected note that rounds out the savory beef broth. The soup simmers for 30 minutes, long enough for the onion flavors to meld but short enough that each variety keeps some of its distinct character.

The gratin finish is the classic move: a slice of toasted baguette floats on top, covered in Swiss cheese and Parmesan, then broiled until bubbling and golden.

Chef Tips

• Use only the white portion of the leek. The green tops are tough and fibrous, even after simmering.
• Saute low and slow. You want golden, soft onions, not browned or caramelized. This is a gentler approach than traditional French onion soup.
• Sprinkle Swiss cheese on the bottom of each bowl before ladling in the soup. It melts into the broth and adds richness throughout.
• Watch the broiler closely. The cheese goes from bubbly golden to burnt in about 30 seconds.

Variations

• Add shallots as a fifth onion for even more allium depth.
• Swap Swiss for Gruyere for a more traditional French onion experience.
• Float a poached egg under the bread and cheese for a heartier meal.