French Onion Lyonnaise Potatoes Recipe

The flavor balance between buttery potatoes, caramelized onions, and nutty cheese is deeply savory yet brightened by sherry and thyme.
The method delivers crisp edges and tender centers on the potatoes without greasiness.
It’s elegant enough for entertaining but easy enough for a cozy weeknight meal.

This recipe brings together the two French classics of French onion soup and Lyonnaise potatoes into one gloriously rich and satisfying side. Sweet onions are slowly caramelized until deep golden and jammy, then deglazed with dry sherry for a touch of brightness that echoes the brothiness of the beloved soup. Meanwhile, Yukon Gold potatoes are parboiled for tenderness and pan-fried until their edges turn irresistibly crisp. Once combined, the mix is blanketed in shredded Gruyère and broiled until the cheese bubbles and browns, infusing the dish with the nutty savoriness of fondue. A final sprinkle of fresh thyme provides a fragrant finish that keeps every bite from feeling too heavy.

French Onion Lyonnaise Potatoes are an ideal partner for roast chicken, steak, or a simple green salad. It’s a dish that feels both simple and luxurious, the kind of food that warms your kitchen as it fills the air with buttery, oniony aroma. Developed by Marianne Williams, this dish earned unanimous five-star ratings in our test kitchen for its spot-on balance of flavor, texture, and ease. Whether you serve it for a dinner party or a weekend meal, it’s sure to impress anyone lucky enough to dig in.

Sherry substitutes

If you don’t have dry sherry on hand, several ingredients can replicate its nuanced depth. Chinese shaoxing wine is a surprisingly close match. Dry white wine is also a good option, and you can use an equal amount and add a splash of vinegar for brightness. For a nonalcoholic option, combine low-sodium chicken or beef broth with a teaspoon of sherry vinegar or apple cider vinegar. Dry vermouth or Marsala can also stand in, adding gentle sweetness and complexity similar to sherry’s nutty, savory character.

Why are the potatoes parcooked?

Parcooking potatoes is essential in a Lyonnaise potato recipe to achieve the perfect texture of tender on the inside and crisp on the outside. Boiling the slices briefly before pan-frying ensures they cook evenly and won’t burn before softening. This step also removes some surface starch, helping the potatoes brown more evenly in the skillet. The result is a consistent, golden crust that holds together beautifully while staying creamy and flavorful within each bite.