French Onion Soup Potatoes (Printable Copy)

Roasted potato slices with caramelized onions and melted Gruyère cheese, inspired by classic French flavors.

# What You 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)

# How to Make:

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 Advice:

01 -
  • The onions do most of the heavy lifting while you roast the potatoes, so you're not stuck at the stove the whole time.
  • It tastes like restaurant-quality comfort food but comes together without any fussy techniques or special equipment.
  • Vegetarian, naturally gluten-free, and flexible enough to work alongside almost any main course you're planning.
02 -
  • Caramelizing onions takes actual time, not the 10 minutes you might hope for—rush it and you'll have brown onions instead of sweet, golden ones, which changes the entire dish.
  • Slice your potatoes evenly so they cook at the same rate; thick pieces stay raw while thin ones turn to mush, so a sharp knife or mandoline is worth your attention here.
03 -
  • Don't use a food processor to slice the onions unless you want onion paste—a sharp knife and a little patience create the long, silky slices that caramelize beautifully.
  • Keep the oven door closed during the final cheese bake; every time you peek, heat escapes and the cooking time stretches, so trust the process and check at the 10-minute mark.
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