French Onion Soup Potatoes (Printable)

Roasted potato slices with deeply caramelized onions and bubbling Gruyère cheese, inspired by French onion soup flavors.

# What You'll Need:

→ 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)

# Directions:

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 Tips:

01 -
  • It borrows all the deep, sweet, savory magic of French onion soup but skips the broth and bread.
  • The Gruyère gets gloriously bubbly and golden on top, creating those irresistible cheese pulls.
  • You can prep the onions ahead and just assemble everything before guests arrive.
  • It works as a hearty side or a vegetarian main with a simple salad on the side.
02 -
  • Don't rush the onions; if you crank the heat too high, they'll brown unevenly and taste bitter instead of sweet.
  • Slice the potatoes as evenly as possible so they cook at the same rate, or you'll end up with some mushy and some still hard.
  • Let the dish rest for a few minutes after baking so the cheese sets slightly and doesn't slide off when you serve it.
03 -
  • Use a mandoline to slice the potatoes evenly if you have one, it makes a noticeable difference in how uniformly they cook.
  • If your skillet isn't big enough for all the onions at once, cook them in two batches so they caramelize properly instead of steaming.
  • Grate the Gruyère yourself instead of buying pre-shredded; it melts smoother and tastes fresher.
Go Back