My husband said these are better than any steakhouse side he has ever had. The caramelized onion flavor is absolutely unreal!

Spray the inside of a 4- to 6-quart slow cooker with nonstick cooking spray to help prevent sticking and make cleanup easier.

Wash the Yukon gold potatoes and thinly slice them into 1/8–1/4-inch rounds, leaving the skins on for extra texture and to save time. Pat dry with a clean towel if very wet so they don’t steam too much.

In a medium bowl, whisk together the dry French onion soup mix and melted butter until the soup mix is evenly moistened and no big dry clumps remain. This creates a rich, concentrated “caramelized onion” sauce that will coat the potatoes as they cook.

Spread a thin, even layer of sliced potatoes over the bottom of the slow cooker. Drizzle a few spoonfuls of the onion-butter mixture over the potatoes, using the back of the spoon to spread it so most slices get some coverage.

Sprinkle a small handful (about 1/2 cup) of the shredded Gruyère over this first layer of potatoes. This helps create those cheesy, melty pockets all the way through, not just on top.

Repeat layering: potatoes, onion-butter mixture, and a small sprinkle of Gruyère, until you’ve used all the potatoes and onion-butter mixture. Reserve at least 1 cup of Gruyère for the very top layer so you get that bubbly, browned cheese finish.

Finish with the remaining Gruyère cheese in an even layer over the top of the potatoes. This top layer is what will turn deep golden and slightly crisp around the edges, just like a steakhouse gratin.

Cover the slow cooker with the lid and cook on LOW for 5 to 6 hours, or on HIGH for 2 1/2 to 3 hours, until the potatoes are very tender when pierced with a fork and the edges of the cheese around the sides are deep golden and bubbly.

If you want a more browned top, once the potatoes are fully cooked, carefully remove the ceramic insert from the slow cooker (if it’s oven-safe) and place it under the oven broiler for 3 to 5 minutes, watching closely, until the cheese is extra bubbly and browned on top. This step is optional but really drives home that steakhouse look and flavor.

Let the potatoes rest, uncovered, for about 10 minutes before serving so the cheesy, oniony sauce thickens slightly and the layers hold together better when scooped. Serve straight from the slow cooker on warm for easy, help-yourself family dinners or gatherings.

Variations & Tips