Crispy Pommes Lyonnaise with Caramelized Onions Step-by-step instructions

Before you start

Before starting, gather all ingredients and equipment. Scrub the potatoes clean and set them in a large pot. Have the onions sliced, the butter measured, and the parsley chopped. Clear your workspace so you can move quickly between steps.

The entire process takes about 45 minutes, most of which is hands-off cooking. Make sure you have a wide skillet ready, as it will be used for both the onions and the potatoes. If using clarified butter, you can prepare it ahead or purchase it ready-made.

Instructions

Phase 1: Prep and Caramelize

1. 1Parboil and slice the potatoes
   Scrub the potatoes but leave the skins on. Place them in a large pot and cover with cold water by 1 inch. Bring to a boil, then reduce to a simmer and cook for 12 minutes, until a knife pierces with slight resistance. Drain and let cool just enough to handle. Peel the potatoes and slice into 1/4-inch (6 mm) coins.
   Look for Potatoes are tender but still hold their shape when pierced.
   Tip Cooling slightly makes peeling easier; use a paring knife to pull off the skins.
2. 2Caramelize the onions
   In a wide skillet, melt the 2 tbsp butter over medium heat. Add the sliced onions and cook slowly, stirring occasionally, for 20 minutes, until they are deeply golden and jammy. Reduce heat if they start to brown too quickly. Transfer the onions to a plate and set aside.
   Look for Onions are soft, sweet, and deep amber in color.
   Tip Patience is key; low heat prevents burning and brings out natural sweetness.

At the end of this phase, the potatoes are parboiled and sliced into neat coins, and the onions are glossy, deeply browned, and sweetly fragrant. The kitchen smells of slowly caramelizing onions—rich, buttery, and inviting.

The onions should be soft and jammy, with no crunch remaining. The potatoes are cool enough to handle but still warm inside. This is the foundation of the dish; take your time with the onions to build maximum flavor.

Phase 2: Sear and Fold

3. 3Sauté the potato coins
   Wipe the skillet clean and heat the clarified butter over medium-high heat until shimmering. Add the potato coins in a single layer (work in batches if needed) and cook for 5 minutes per side, until both flat faces are golden brown and crispy. Adjust heat to maintain a steady sizzle without burning.
   Look for Edges turn deep golden and crisp; the centers are tender.
   Tip Do not overcrowd the pan; give each coin room to develop a crust.
4. 4Fold in the onions
   Return the caramelized onions to the skillet with the potatoes. Gently fold everything together, allowing the onions to warm through and coat the potatoes. Season lightly with fleur de sel if desired, keeping in mind the onions may already add saltiness.
   Look for Onions and potatoes are evenly distributed and fragrant.
   Tip Fold gently to keep potato coins intact.

The potato coins are now crisp and golden on both sides, sizzling in clarified butter with a crackling sound that signals success. The edges are deep brown and shatter when pressed. When the onions are folded in, the mixture becomes fragrant with sweet caramel notes mingling with the buttery potatoes. The skillet should be glossy, with no excess butter. Everything is hot and ready for the final touch.

Phase 3: Finish and Serve

5. 5Finish with parsley and serve
   Remove the skillet from heat and toss with the chopped parsley. Transfer to a serving platter or individual plates. Finish with a final sprinkle of fleur de sel just before serving. Serve hot and enjoy the contrast of crispy potatoes and sweet onions.
   Look for Parsley brightens the dish; potatoes are crispy on the outside, tender inside.
   Tip Serve immediately for maximum crispness.

The finished dish is vibrant with fresh parsley and a final sprinkle of fleur de sel. The potatoes remain crispy, the onions are sweet and tender, and the entire dish glistens appetizingly. The aroma is irresistible—buttery, savory, and slightly sweet. Serve immediately, as the crispness is at its peak. The contrast of textures and flavors is the hallmark of a perfect pommes lyonnaise.

Common mistakes

One common mistake is overcrowding the skillet, which causes the potatoes to steam instead of crisp. Work in batches if necessary. Another is using too low a heat for the potatoes; you want a steady sizzle to develop that golden crust.

Conversely, the onions need low heat—rushing them leads to burnt edges and raw centers. Finally, avoid peeling the potatoes before parboiling; the skins help them hold together. If you skip the parboil, the potatoes will not cook through evenly.

How to tell it’s done

The potatoes are done when they are deeply golden brown on both flat faces and have a crisp, crackling crust. The centers should be tender and creamy, easily pierced with a fork. The onions should be soft, deeply caramelized, and almost jammy in texture, with a sweet, rich aroma.

When you fold the onions with the potatoes, the mixture should be glossy and fragrant. If you are cooking for a crowd, keep the potatoes warm in a low oven (200°F / 95°C) for up to 20 minutes, but serve as soon as possible for maximum crispness.