French Onion Soup Potatoes (Printable version)

Golden roasted potatoes with caramelized onions and melted Gruyère cheese, inspired by classic French onion soup flavors.

# Needed ingredients:

→ Potatoes

01 - 3.3 lbs Yukon Gold or russet potatoes, scrubbed and sliced 1/3 inch thick
02 - 2 tbsp olive oil
03 - 1/2 tsp kosher salt
04 - 1/4 tsp freshly ground black pepper

→ Caramelized Onions

05 - 3 large yellow onions, thinly sliced
06 - 2 tbsp unsalted butter
07 - 1 tbsp olive oil
08 - 1/2 tsp kosher salt
09 - 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
10 - 1 tsp balsamic vinegar

→ Topping

11 - 7 oz Gruyère cheese, grated
12 - 1 oz Parmesan cheese, grated (optional)
13 - 2 tbsp chopped fresh parsley (for garnish)

# How to make it:

01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper.
02 - Toss potato slices with olive oil, salt, and pepper. Arrange in a single layer on the prepared sheet. Roast for 25-30 minutes, flipping once, until golden and tender.
03 - While potatoes roast, heat butter and 1 tbsp oil in a large skillet over medium-low heat. Add onions and salt; cook, stirring often, for 25-30 minutes until deeply golden and caramelized. Stir in thyme and balsamic vinegar; cook 1-2 minutes more. Remove from heat.
04 - Reduce oven temperature to 400°F.
05 - Arrange roasted potato slices in a lightly greased baking dish, slightly overlapping. Spoon caramelized onions evenly over the potatoes. Sprinkle Gruyère (and Parmesan, if using) over the top.
06 - Bake for 10-15 minutes until cheese is melted and bubbling.
07 - Let cool slightly. Garnish with chopped parsley and serve warm.

# Expert Suggestions:

01 -
  • It takes the soul of French onion soup and turns it into something you can serve alongside anything or eat straight from the pan.
  • The potatoes get crispy on the edges while staying tender inside, and the caramelized onions add a sweetness that feels almost luxurious.
  • You can prep the onions ahead and assemble everything in minutes when guests arrive.
  • It works as a vegetarian main or a show-stopping side that makes people forget about plain roasted potatoes forever.
02 -
  • Don't rush the onions; if you try to speed them up over high heat, they'll burn instead of caramelizing and you'll lose that sweet depth.
  • Make sure the potato slices are all roughly the same thickness so they roast evenly; uneven pieces mean some will be mushy while others are still hard.
  • If your baking dish is too small and the potatoes are piled too high, the cheese won't reach all the layers and the bottom will stay dry.
03 -
  • Use a mandoline to slice the potatoes if you have one; it keeps them uniform and makes the roasting faster and more even.
  • If the onions start to stick or look dry while caramelizing, add a tablespoon of water or broth to deglaze the pan and keep them from burning.
  • Let the assembled dish rest for five minutes after baking so the cheese firms up just enough to serve without everything sliding apart.
Go back