These oven-baked 3-ingredient Lyonnaise potatoes are a streamlined, home-oven version of a classic French dish from the Lyon region. Known for their simple combination of potatoes, onions, and fat, this version is layered in a casserole dish and baked until the onions are deeply golden and the potatoes are tender with crisp, browned edges. It’s the kind of comforting recipe you make once and then keep in your back pocket for roast chicken nights, potlucks, or anytime you want something elegant without a lot of fuss.
Why You’ll Love This Recipe
- 🥔 Classic Comfort: Brings the traditional spirit of French Lyonnaise potatoes to your table with minimal effort.
- 🧅 Golden & Flavorful: The slow bake allows the onions to turn deeply golden and sweet, naturally infusing the potatoes with flavor.
- ⏱️ Hands-Off Baking: Streamlined for a home oven, eliminating the need to stand over a hot stove babysitting a skillet.
- 🍽️ Highly Versatile: Pairs perfectly with roasted meats, soft-scrambled eggs for brunch, or a crisp green salad to cut through the richness.
What You’ll Need
- 2 lbs Russet or Yukon Gold potatoes: Peeled (if desired) and thinly sliced into 1/8-inch rounds.
- 2 Large yellow onions: Thinly sliced pole-to-pole (root to stem).
- 6 tbsp Unsalted butter: Melted, plus a little extra for greasing your baking dish.
- Seasonings: 1 ¼ teaspoons kosher salt (or to taste) and ½ teaspoon freshly ground black pepper (optional but recommended).
How to Make It (Step-by-Step)
Prep time: 15 minutes | Cook time: 1 hour 10 minutes | Yield: 4 Servings
Step 1: Prep and Preheat
Preheat your oven to 375°F (190°C). Lightly grease a vintage-style oval casserole dish or any similar 2-quart baking dish with a bit of butter, making sure to coat the bottom and sides so the potatoes don’t stick.
Step 2: Slice the Vegetables
Prepare the potatoes by slicing them into thin rounds about 1/8 inch thick. Try to keep them as even as possible so they cook at the same rate. Slice the onions from root to stem (pole-to-pole) so they hold their structure as they soften.
Step 3: Toss and Coat
In a large bowl, add the sliced potatoes and onions. Drizzle with the melted butter, then sprinkle in the kosher salt and black pepper. Toss gently with your hands to coat every slice so both the onions and potatoes get enough fat to brown properly.
Step 4: Layer the Dish
Arrange a snug layer of potato slices over the bottom of the prepared casserole dish, overlapping them slightly like shingles. Scatter a loose, even layer of onions over the potatoes. Repeat this process until you’ve used everything, finishing with a layer of potatoes on top. Pour any remaining butter from the bowl evenly over the top.
Step 5: The Covered Bake
Cover the dish tightly with foil and bake for 30 minutes. This covered time allows the potatoes to steam and soften while the onions begin to collapse and sweeten without drying out.
Step 6: The Uncovered Bake
Remove the foil and return the dish to the oven. Continue baking uncovered for 30 to 40 minutes, rotating the dish once halfway through.
💡 Crucial Step: Watch for the visual cues! The onions should turn a deep, even golden color and the edges of the potato slices should crisp and brown. This is the key step—don’t rush it.
Step 7: Rest and Serve
Let the Lyonnaise potatoes rest for at least 10 minutes before serving. This short rest helps the layers settle so you can scoop out neat portions and ensures the butter redistributes. Serve warm!
💡 Expert Tips for Success
- 🛑 Tuck the Onions: When finishing your final layer, tuck any stray onion pieces between the top potato slices so they don’t burn in the oven.
- 🔪 Check for Doneness: Slide the tip of a knife into the center of the dish; it should glide through the potatoes with almost no resistance.
- 🔥 Achieve Deeper Browning: If the potatoes are tender but you’d like more color, move the dish to the upper third of the oven for the last 5 to 10 minutes to encourage deeper browning on the edges.
Variations and Substitutions
- Olive Oil Swap: Swap half of the butter for a fruity extra-virgin olive oil to shift the flavor toward a more Mediterranean profile.
- Herb-Forward Twist: Sprinkle 1 to 2 teaspoons of fresh thyme leaves or finely chopped rosemary between the layers with the salt and pepper.
- Subtle Garlic Note: Lightly crush 2 garlic cloves and tuck them into the dish near the sides so they infuse the butter (remove before serving if you don’t want to bite into them).
❓ Frequently Asked Questions (FAQs)
Can I make this dish ahead of time?
Yes! You can assemble the dish up to the point of baking, cover it tightly with foil, and refrigerate it for up to 8 hours. When you are ready to bake, add an extra 5 to 10 minutes to the initial covered baking time since it will be starting cold.
How do I store and reheat leftovers?
Cool any leftovers quickly and refrigerate within 2 hours of baking in a shallow container. They will keep safely for about 3 to 4 days. Reheat thoroughly in a 350°F (175°C) oven until steaming hot in the center, which improves both safety and texture compared to microwaving alone.
Conclusion
Classic Lyonnaise potatoes are a testament to the magic of simple ingredients. By taking the time to layer thinly sliced potatoes and onions with rich butter, you create a side dish that steals the show at any dinner table. Grab your mandoline, melt that butter, and get ready for a plate of pure, quiet comfort!