Cheesy French Onion Baked Potatoes

published Dec 10, 2023
French Onion Baked Potatoes Recipe

Jammy caramelized onions plus gooey Gruyère = a dreamy baked potato.

Serves4

Prep20 minutes to 25 minutes

Cook2 hours 15 minutes to 2 hours 25 minutes

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French Onion Baked Potato on plate
Credit: Kelli Foster

Every good thing that comes out of my kitchen starts with onions (excluding sweets, of course!). So whenever I don’t have a clue about what to make for dinner, an onion is where I begin. Luckily with a little bit of butter, a fluffy baked potato, and some time (as well as the herby kind of thyme, too), it’s easy to turn an onion into a ridiculously delicious dinner. This recipe for French onion baked potatoes takes the best parts of the iconic soup — sweet caramelized onions and gooey Gruyère cheese — and puts them on a baked potato. 

This is the recipe to make when your pantry is bare, but you have some time to spend in the kitchen coaxing the most flavor from just a few ingredients. Here’s how to take the best baked potato recipe and make it 100 times better. 

How to Make the Best Baked Potato

There’s a lot more to making the best-ever baked potatoes than just tossing them in the oven. If you want a baked potato with an impossibly fluffy interior and crispy, crunchy skin, you have to bake them like the British do. Luckily, English jacket potatoes are easy to make if you follow three simple tips.

  • Slice before baking. Don’t poke the potatoes with a fork. Instead, cut a cross-shape into the surface of one side of the potato to allow steam to escape.
  • Bake for a long time. Push the baked potatoes beyond “done” by cooking for far longer than you normally would. After about two hours in the oven, the interior is soft and light while the skin is crackly crisp.
  • And then bake again. Slice a little deeper into the initial cut, then return the potatoes to the oven. The second round of baking dries the potato flesh even more for the fluffiest baked potatoes ever. 

What Is French Onion?

French onion refers to the iconic French onion soup made from caramelized onions and beef broth, and topped with a Gruyère cheese-covered crouton. Caramelized onions are key to the rich, savory-sweet, and caramel flavor of the soup. 

How to Caramelize Onions

The secret to perfectly caramelized onions is time and patience. Cook sliced onions in butter over moderate heat for a long time, at least 30 minutes. During this time, moisture from the onions evaporates and the sugars brown, caramelize, and develop their signature complex flavor. 

What Is the Difference Between Caramelized and Sautéed Onions?  

  • Caramelized onions: Cooked over moderate heat for an extended period of time. Caramelized onions are deep golden or mahogany in color and have a soft, jammy consistency.
  • Sautéed onions: Cooked over higher heat for a shorter amount of time. Onion texture is firmer and color ranges from translucent to golden-brown.

More French Onion Recipes to Try

French Onion Baked Potatoes Recipe

Jammy caramelized onions plus gooey Gruyère = a dreamy baked potato.

Prep time 20 minutes to 25 minutes

Cook time 2 hours 15 minutes to 2 hours 25 minutes

Serves 4

Nutritional Info

Ingredients

  • 4

    medium russet potatoes (8 to 10 ounces each)

  • 1 pound

    yellow onions (about 1 large or 2 medium)

  • 1/2 small bunch

    fresh thyme (about 10 sprigs), plus more for serving

  • 1 clove

    garlic

  • 2 ounces

    Gruyère cheese

  • 4 tablespoons

    unsalted butter, divided

  • 1/2 teaspoon

    kosher salt, plus more for the potatoes

  • 1/2 teaspoon

    freshly ground black pepper, plus more for the potatoes

  • 1 tablespoon

    all-purpose flour

  • 1 cup

    beef broth

  • 1/2 teaspoon

    balsamic or sherry vinegar

Instructions

  1. Arrange one oven rack 6 to 8 inches from the broiler and a second rack in the middle of the oven. Heat the oven to 400°F.

  2. Prepare 4 medium russet potatoes: Scrub the potatoes, then cut a cross shape about 1/4-inch deep into each potato, leaving half an inch border. Place the potatoes cut-side up directly onto the middle oven rack. Bake until very crisp and crackly on the outside, about 2 hours.

  3. When the potatoes have about 30 minutes remaining, halve and thinly slice 1 pound yellow onions (about 4 cups). Pick the leaves from 1/2 small bunch fresh thyme until you have 1 tablespoon. Mince 1 garlic clove. Grate 2 ounces Gruyère cheese on the large holes of a box grater (heaping 1/2 cup).

  4. Melt 2 tablespoons of the unsalted butter in a 12-inch cast iron or other broiler-safe, heavy-bottomed skillet over medium heat. Add the onions, thyme, 1/2 teaspoon kosher salt, and 1/2 teaspoon black pepper. Cook, stirring frequently with a wooden spoon and reducing the heat if the onions start to brown too quickly, until the onions have reduced by over half, are very soft, and deep golden-brown, 25 to 30 minutes.

  5. Add the garlic and 1 tablespoon all-purpose flour and stir until the flour is completely incorporated, leaves a film on the bottom of the skillet, and begins to brown, about 1 minute. Add 1 cup beef broth and scrape up any browned bits on the bottom of the skillet. Increase the heat back to medium if it was lowered while cooking the onions. Bring to a boil. Simmer until the sauce is thickened enough to coat the back of a spoon, about 3 minutes.

  6. Remove the pan from the heat. Add 1/2 teaspoon balsamic or sherry vinegar and stir to combine. Taste and season with more kosher salt and black pepper as needed.

  7. Carefully remove the potatoes from the oven with tongs and place on a baking sheet. Carefully cut deeper into the cuts you made initially. Gently push the two opposite ends of each potato toward each other to open them, release steam, and expose some of the flesh.

  8. Return the potatoes to the lower oven rack and bake for 10 minutes more. Remove them from the oven. Push the two opposite ends of each potato toward each other again to open them fully. Cut the remaining 2 tablespoons unsalted butter into 4 pieces, and add one piece to each potato. Add a pinch of kosher salt and black pepper to each potato. Evenly divide the onion mixture between the potatoes (about 1/4 cup per potato), and top evenly with the cheese.

  9. Turn the oven to broil. Transfer the baking sheet to the upper rack and broil until the cheese is melted, bubbly, and browned in spots, 3 to 4 minutes. Garnish with more fresh thyme leaves if desired.

Recipe Notes

Make ahead: The onion mixture can be prepared up to 2 days ahead and refrigerated in an airtight container. Let sit at room temperature for 30 minutes, or reheat in the microwave for 30 to 40 seconds before topping the potatoes.

Storage: Leftovers can be refrigerated in an airtight container for up to 4 days.