Cheesy French Onion Potato Casserole
This cheesy French onion potato casserole combines tender potatoes with a rich, creamy French onion sauce, plenty of melted Gruyère, Swiss, and cheddar cheese, and a crispy fried onion topping. It's an easy, comforting side dish that's perfect for holidays, potlucks, and family dinners.
Equipment
Ingredients
- 1 10.5-ounce can condensed French onion soup
- 1 packet Lipton Recipe Secrets Onion Soup Mix
- 1 ½ cups heavy cream
- 1 cup sour cream
- 1 tsp Worcestershire sauce
- 1 tsp garlic powder
- ½ tsp black pepper
- 3 pounds Yukon Gold potatoes peeled and sliced ⅛-inch thick
- 1 cup shredded Gruyère cheese
- 1 cup shredded Swiss cheese
- 2 cups shredded mozzarella divided
- ½ cup grated Parmesan cheese
Topping
- 1 ½ cups crispy fried onions optional
- Parsley optional
Instructions
- Preheat the oven to 350°F. Grease a 9x13-inch baking dish.
- In a large bowl, whisk together the condensed French onion soup, onion soup mix, heavy cream, sour cream, Worcestershire sauce, garlic powder, and black pepper until smooth.
- Stir in the Gruyère cheese, Swiss cheese, 1½ cups of the cheddar cheese, and the Parmesan cheese.
- Arrange one-third of the sliced potatoes in the prepared baking dish.
- Spoon one-third of the cheese sauce evenly over the potatoes.
- Repeat the layers two more times, ending with the remaining cheese sauce.
- Cover tightly with foil and bake for 70 minutes.
- Remove the foil and check that the potatoes are nearly fork tender.
- Sprinkle the remaining ½ cup cheddar cheese evenly over the top.
- Return to the oven, uncovered, for 15–20 minutes, until the potatoes are tender and the cheese is bubbling.
- Let the casserole rest for 15 minutes before serving.
Notes
- Slice the potatoes as evenly as possible so they cook at the same rate.
- Freshly shredded cheese melts much smoother than bagged cheese.
- Keep the casserole tightly covered for most of the bake so the potatoes steam until tender.
- Let the casserole rest before serving to allow the sauce to thicken.
- If your potatoes are sliced a little thicker, they may need an extra 10–15 minutes of covered baking time.
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