My grandmother made these every Sunday after church. The secret is letting the onions get perfectly golden.

This Oven Baked Lyonnaise Potatoes recipe is a magnificent, classic French country dish that transforms humble root vegetables into an elegant, comforting masterpiece. By layering paper-thin potato rounds with sweet, pole-to-pole sliced yellow onions and rich melted butter, you create a beautiful harmony of textures. The initial covered bake steam-cooks the spuds into a velvety, melt-in-your-mouth interior while allowing the onions to collapse and sweeten. Once the foil canopy is removed, the high oven heat crisps the edges of the potatoes into a deep golden-brown shatter while beautifully caramelizing the onions. It is an exceptionally high-reward side dish that delivers ultimate luxury with absolute minimal active kitchen maintenance.

Oven Baked 3-Ingredients Lyonnaise Potatoes

Ingredients:

Step-by-Step Directions:

Step 1: Prep the Casserole Canopy: Preheat your oven to 375°F. Lightly grease the interior of a 2-quart casserole dish with a smear of butter, coating both the bottom and sides thoroughly to guarantee the starches release cleanly after baking.

Step 2: Slice the Medley Uniformly: Using a sharp knife or a mandoline, slice your potatoes into uniform rounds exactly 1/8- / inch thick. Next, slice your yellow onions from root to stem (pole-to-pole) into thin strips.

A Friendly Kitchen Note: Cutting onions pole-to-pole is a brilliant culinary trick! It ensures the onion fibers retain their structural integrity as they bake, allowing them to turn beautifully golden and sweet rather than completely disintegrating into mush.

Step 3: Toss and Coat the Starches: In a large mixing bowl, combine your sliced potatoes and onions. Drizzle the 6 / tablespoons of melted unsalted butter over the top, then sprinkle in the kosher salt and black pepper. Toss gently with your hands to ensure every single slice of potato and onion is thoroughly glistening with fat, which is critical for even browning.

Step 4: Build the Shingle Layers: Arrange a snug layer of potato slices across the bottom of the prepared dish, overlapping them slightly like shingles on a roof. Scatter a loose, even layer of onions over the potatoes, maximizing the contact points between the two. Repeat this alternating layering process until all ingredients are used, finishing with a neat layer of potatoes on top. Tuck any stray onion pieces beneath the top potato layer to prevent them from burning, and pour any remaining butter from the bowl over the surface.

Step 5: The Steaming Foil Bake: Cover the dish tightly with a sheet of aluminum foil. Slide it onto the center rack of your preheated oven and bake for 30 / minutes. This trapped, high-moisture environment allows the potatoes to steam until tender while the onion sugars slowly collapse and sweeten without drying out.

Step 6: The Uncovered Golden Crisp: Carefully pull away the foil and return the dish to the oven uncovered. Bake for an additional 30 / to 40 / minutes, rotating the dish halfway through. Watch for your visual cues: the onions should turn a gorgeous caramel-golden hue and the edges of the top potatoes should look beautifully crinkled, brown, and crisp.

Step 7: The Tenderness Test: Slide the tip of a sharp paring knife straight down into the center of the dish; it should glide through all the potato layers with absolutely zero resistance. If the spuds are tender but you desire a deeper, crunchier color canopy, simply move the casserole dish to the upper third of your oven for the final 5 / to 10 / minutes to catch a blast of intense top heat.

Step 8: Rest and Redistribute: Remove the bubbling dish from the oven and let it sit completely undisturbed on the counter for at least 10 / minutes. This resting window allows the layers to cool slightly and settle so you can scoop out neat, defined portions, while ensuring the rich butter fat redistributes evenly through the potato matrix instead of pooling at the bottom. Serve warm!