Cheesy French Onion Potato Bake

How to make a French onion potato bake with soup mix

Creating this potato casserole isn’t difficult, but it does have quite a few steps. To make things easier, I separated out the instructions into sections. That way, you can easily follow along with our directions.

Prep the Potatoes:

First, start by boiling the potatoes in a large stockpot filled with water. Use high heat for the quickest results. The potatoes will need to boil for 12-15 minutes or until they’re fork tender.

Meanwhile, preheat your oven to 350°F, and grease an 8×8-inch square baking dish with non-stick cooking spray.

Once the potatoes are done, remove them from the heat and transfer them to an ice bath. Let them chill until they’re cool enough to handle. Afterward, peel the potatoes and slice them into 1/8-inch circular pieces. Set them aside for now. You can make the sauce while the potatoes boil.

Make the Cheese Sauce:

Next, place a medium skillet over low-medium heat. Place the butter into the pan and let it melt. After that, whisk in the flour and let it cook for 2-3 minutes to create your roux.

Now, while whisking continuously, pour in the heavy cream and milk. Go ahead and stir in the onion soup mix. When the liquid begins to steam, start adding the shredded Gruyere cheese. You can use another cheese like Swiss or Fontina.

I recommend sprinkling in 1 handful of cheese at a time. Whisk the mixture until the Gruyere has melted. Continue the process until you’ve added all the shredded cheese to the sauce. Then remove the skillet from the heat.

Build the Casserole:

It’s time to begin layering your potatoes, onions, and sauce into the baking dish. Kim placed 1/3 of each ingredient into every layer.

So, it goes sliced potatoes, onions, and then cheese sauce. Repeat the same process over and over again until the ingredients are gone.

Bake the Casserole and Serve:

To finish off the casserole, she added more shredded Gruyere cheese. You can even add some breadcrumbs for a crunchy topping. Place the potato bake into the oven (uncovered) and let it cook for about 30-minutes until the potatoes are cooked through.

Remove the casserole from the oven and let it cool for a few minutes before serving. That’s it, your French onion potato bake is done! Kim and I hope you enjoy it and wish you all the best.

Storage and Reheating

Store leftovers in an airtight container in the fridge for up to 3 days.

Reheat single servings in the microwave in short bursts. For larger amounts, cover the dish with foil and warm it in a 350°F oven until heated through.

I don’t recommend freezing this one. Cream-based sauces tend to separate after thawing.

Recipe Tips:

• If you don’t have a digital kitchen scale, then 2 pounds of Yukon potatoes comes out to about 12 small potatoes or 6-8 medium potatoes.
• Whether you make 2 or 3 layers for this casserole is up to you. In fact, if you’re using a large casserole dish, then you may only have 1-2 layers.
• The amount of layers in the dish may effect the baking time. Be sure to keep an eye on the casserole as it bakes; otherwise, it may scorch.

What can I use in place of Gruyere?

Swiss and Fontina both have a creamy texture and flavor similar to Gruyere. White cheddar has a different flavor but is really delicious with the French onion mix.