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Food & Recipes

French Onion Potatoes Are a Cozy, Cheesy Twist on a Classic — Easy One-Pan Recipe

Plus, learn expert tips on roasting potatoes and how to make smashed potatoes!

Weeknight dinners often fall into a predictable pattern: a repeat of dishes we know we love, but maybe don’t love love. But tonight, why not break the cycle with a side dish that combines two favorites into one: French onion potatoes. That’s right, oven roasted potatoes can be elevated too. Crispy, buttery wedges of golden potato bathed in a rich caramelized onion sauce with gooey cheese melted on top — it has all the comforting flavors of French onion soup in bite-sized pieces. Our favorite recipe needs only 5 ingredients and can be prepared in one baking dish, making cleanup a breeze. Plus, we’ll share some expert tips for roasting potatoes and the secret ingredient that makes them taste even better: homemade roasted garlic butter. Here’s everything you need to know to make French onion potatoes.

What are French onion potatoes?

We bet you haven’t had potatoes quite like these. French onion potatoes offer a delicious and creative side dish combining the essence of French onion soup in a casserole. It usually includes roasted, diced potatoes bathed in a savory French onion soup sauce (usually canned soup or dry mix with caramelized onions). A combination of butter, cream and melted Gruyère cheese add a rich, creamy texture to the base. Before fully baked, the dish gets topped with more shredded cheese for a golden-brown crust. And the best part has it be it doesn’t take long to prep or a ton of ingredients. No wonder it became viral on TikTok!

See also: French Onion Pasta Is Pure Comfort on a Plate — One-Pot Recipe Is Fast + Delicious

The history of French onion soup

Onion soups can be traced back to Roman peasant cuisine, usually consisting of a simple broth of onions and water. But over time, the recipe evolved in France among the upper-class, incorporating browned onions and a generous amount of butter for a deeper flavor profile. The iconic addition of toasted bread and melted cheese, known as a gratin, on top emerged in the 18th century and became a staple in Parisian cafés.

Craving the original? Try our warm and cheesy classic French onion soup recipe.

Tips for perfectly roasted potatoes

french onion casserole: roasted-potatoes
Marko Jan/Getty

Roasted potatoes, when done right, offer a crispy, textural contrast to the French onion sauce. We recommend this step so the potatoes can hold up against the heavy components and don’t become too mushy. Additionally, it adds extra flavor beyond just absorbing the sauce. Here, some tips from Gen La Rocca, chef and owner of Two Cloves Kitchen, to ensure your roasted potatoes turn out perfectly.

1. Choose the right potatoes

“My favorite potatoes for roasting are small, waxy potatoes like fingerling or Yukon Gold potatoes,” says La Rocca. “They hold their shape well and have a lovely, creamy texture.” Alternatively, you can also russet potatoes. They also have a high starch content, which helps create a fluffy interior and crispy exterior when roasted. Their robust texture also holds up well to the oven’s heat and the sauce.

2. Parboil before roasting

Parboiling the diced potatoes before roasting changes the game when it comes to texture. It involves partially cooking the potatoes in boiling water for a few minutes before transferring them to the oven. Parboiling softens the exterior of the potatoes, allowing them to crisp up more effectively during roasting. It also helps ensure they cook evenly, preventing them from becoming mushy on the inside while waiting for the outside to brown.

3. Use high heat

Roasted potatoes require a hot oven. You should set it to around 425°F, which ensures that the potatoes cook quickly and evenly. The high heat encourages caramelization, giving the potatoes that ideal golden-brown color and enhanced flavor.

If you want to make your own caramelized onions, note that they require slow-and-slow cooking. La Rocca recommends being “patient when caramelizing your onions…You will need to cook [them] on medium-low to low for at least 45-50 minutes.”

4. Use seasoning and fat

Potatoes on their own need a little love, even when roasted. “My best tip for roasting potatoes is to use adequate fat,” adds La Rocca. “Be sure the potatoes are evenly coated in olive oil (or avocado oil) before roasting so they cook evenly, develop a crisp, golden-brown exterior, and retain their moisture. Roasting potatoes without enough fat can result in dry, soft potatoes.”

We also suggest using butter for a richer flavor (keep reading for our garlic roasted version below!). And don’t skimp on the seasoning — be liberal with salt, pepper and any other herbs or spices you prefer. Seasonings enhance the taste and give a crispy texture.

The secret ingredient: roasted garlic butter

Want to take your French onion potatoes to the next level? We have a secret ingredient: compound butter. Specifically, roasted garlic butter. It will add an incredible flavor to both the potatoes and the sauce, especially if you roast your potatoes in it before adding to the sauce.

What is compound butter?

Compound butter, also known as flavored butter, combines softened butter with a variety of flavorings, such as vegetables, herbs, spices or citrus zest, to create a versatile condiment that enhances the taste of any dish. Whether slathered on crusty bread, melted over grilled steak or incorporated into recipes (like this one), it adds a burst of flavor. Because who wouldn’t want elevated butter? Plus, it doesn’t take much effort to make your own at home with any customizations you want.

Roasted garlic butter recipe

We don’t think it gets any better than roasted garlic. This easy recipe from Foolproof Living mixes garlic with creamy butter and fresh herbs. Spread it over your potatoes before roasting or add it to your French onion sauce!


  • 1 whole garlic bulb
  • 1 tsp. olive oil
  • 4 oz. unsalted butter, at room temperature (1 stick)
  • ½ tsp. kosher salt or sea salt
  • ¼ tsp. black pepper
  • 2 tsp. chopped fresh herbs rosemary, chives and parsley


  • Active Time: 5 minutes
  • Total Time: 3 hours, 45 minutes (including chilling)
  • Yield: 4 oz butter (1 stick)
  1. Preheat oven to 400°F. Then slice the top off the garlic and place it on aluminum foil. Pour olive oil over and wrap it tightly. Place on a baking sheet and roast for 40 minutes.
  2. Carefully remove the aluminum foil and see if the garlic cloves are softened and lightly caramelized. Then let cool for 10-15 minutes. Gently squeeze the head from the root end, pushing out all the soft cloves until left with the outer skin and discard.
  3. Transfer the roasted garlic into a medium bowl. Using the back of a fork, mash garlic until it is fully pureed.
  4. Add the softened butter, salt, black pepper and chopped herbs, then mix until combined.
  5. You can use the garlic butter immediately or create a compound butter. To do so, place on a piece of plastic wrap (or parchment paper), shape it into a cylinder and wrap it tightly. Chill the compound butter for least 3 hours before using.

Note: You can store your roasted garlic butter in the fridge, either tightly wrapped or in an airtight container, for up to three days. It can also be frozen for up to 1 month. To thaw, transfer to the fridge 1 hour before using.

Easy French onion potatoes recipe

Whether you want to warm up on a chilly night or planning a cozy weekend dinner, this recipe from South Your Mouth does just the trick. It features tender cut potato pieces (though you can roast yours before) cooked in a savory, buttery onion soup base and topped with Gruyère cheese. Serve this alongside your favorite protein like chicken or steak for a hearty dinner.

French Onion Potatoes

french onion potatoes: casserole dish


  • 1 (10-oz.) can French onion soup
  • 1 (1-oz.) envelope dry onion soup mix
  • ½ cup (1 stick) butter, melted
  • 2½ lbs. russet potatoes (6-7 medium-large potatoes)
  • 2 cups shredded Gruyère cheese


  • Active Time: 15 minutes
  • Total Time: 1 hour, 15 minutes
  • Yield: 6 servings
  1. Preheat oven to 375°F. Then combine soup, dry soup mix and melted butter in a large bowl and stir well.
  2. Peel the potatoes, then cut into 1-inch pieces. Add the potatoes to the soup mixture and stir to coat.
  3. Pour everything into a 13×9 inch baking dish, then spread the potatoes evenly along the edges. Cover tightly with aluminum foil, then bake for 30 minutes.
  4. Remove the foil, then continue cooking for 30-45 minutes, or until the potatoes feel tender, stirring 2-3 times to ensure they cook evenly.
  5. Top with shredded cheese, then cover the dish tightly with foil and let the potatoes rest for about 5-10 minutes to soak up the soup mixture and allow for the cheese to melt.

Note: Do not prepare the condensed soup or soup mix; just add to the recipe as-is.

Storage notes

If you have leftover French onion potatoes, allow them to cool to room temperature before transferring them to an airtight container. Store the container in the refrigerator for up to 3-4 days. They can also be frozen for up to 2-3 months.

Reheat your potatoes in the oven for best results. Preheat to 350°F, then place the fully thawed potatoes in a baking dish and cover with foil to prevent drying out. Heat for 15-20 minutes, or until heated through.

How to smash your French onion potatoes

If you want to add a trendy (and delicious) twist to your potato game, you can smash your potatoes before roasting and adding to your French onion soup base. What are smashed potatoes? Potatoes that have been gently smashed to create a flattened, rustic shape. This unique preparation allows for maximum surface area contact with the cooking pan, resulting in irresistibly crispy edges and a fluffy interior. Plus, they can accommodate more flavor in the form of spices, herbs and toppings of your choice (including compound butter).

Learn celebrity chef Rachael Ray’s secrets to the best-ever smashed lemon potatoes. Or check out this TikTok video to learn how to make French onion smashed potatoes.


okay but after trying these french onion smashed potatoes, i never want to eat potatoes any other way 😂 they are the ultimate finger food — make them as a side dish or as a game day appetizer 🥔🧅 RECIPE (gluten free): -1 lb baby potatoes (i really like using the teeny tiny potatoes from trader joe’s) -olive oil -salt + pepper -2 onions, sliced into strips -1/2 cup broth (i used @Dr Kellyann Petrucci french onion bone broth) -3 sprigs of fresh thyme, stems removed + more to top -4 oz shredded low-moisture mozzarella -2 oz swiss cheese (about 2 slices) preheat oven to 390F. bring a large pot of salted water to a boil. once boiling, add potatoes and cook for about 15-20 minutes until fork tender (may take longer if you’re using bigger potatoes). drain and let them sit in the colander for 5 minutes. then, transfer potatoes to a large, greased baking sheet. smush them flat with the bottom of a cup or a fork. spray or brush with a little olive oil. season with salt + pepper. bake for 35 minutes. meanwhile, bring a large, high-sided pan to medium-high heat. once hot, add oil. then add the onion in several batches. after adding each handful of onion, stir and sauté for about 2 minutes. once all onion is added to pan, reduce heat to medium-low and season with salt + pepper. continue stirring every few minutes so they don’t burn. it will take about 20-30 more minutes for them to be caramelized. once onions are a deep, caramelized color, slowly add in the broth. stir. add in fresh thyme and season with more s+p as desired. let that simmer a little longer until the broth is mostly absorbed. place a small amount of the caramelized onions onto each smashed potato, then top with a little piece of swiss and some shredded mozzarella. change the oven to broil and broil for 5-7 minutes, until cheese is golden. top with more thyme leaves. enjoy! #frenchonionsoup #caramelizedonions #smashedpotatoes #gamedayfood #appetizers #glutenfreerecipes #cheesyfood #fallfood

♬ original sound – Maddie

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