# What you'll need:
→ Potatoes
01 - 4 large Yukon Gold potatoes, scrubbed and sliced into ½-inch rounds
02 - 2 tablespoons olive oil
03 - ½ teaspoon kosher salt
04 - ¼ teaspoon black pepper
→ Caramelized Onions
05 - 2 large yellow onions, thinly sliced
06 - 2 tablespoons unsalted butter
07 - 1 tablespoon olive oil
08 - ½ teaspoon sugar
09 - ¼ teaspoon salt
10 - 1 teaspoon fresh thyme leaves or ½ teaspoon dried thyme
→ Topping
11 - 1 cup grated Gruyère cheese (approximately 100 grams)
12 - 2 tablespoons fresh parsley, chopped (optional)
# Method:
01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - Toss potato slices with olive oil, kosher salt, and black pepper in a large bowl. Arrange the slices in a single layer on the prepared baking sheet. Roast for 25 to 30 minutes, flipping halfway through, until golden and tender.
03 - While potatoes roast, heat butter and olive oil in a large skillet over medium-low heat. Add onions and salt, cooking and stirring frequently until softened, about 10 minutes. Add sugar and thyme, cooking further for 20 to 25 minutes until deeply golden and caramelized, adjusting heat as necessary to prevent burning.
04 - Remove roasted potatoes from oven and transfer to a shallow baking dish or ovenproof skillet, layering slices slightly overlapping.
05 - Spread caramelized onions evenly over the potatoes, then top with grated Gruyère cheese.
06 - Return the dish to the oven and bake for 10 to 12 minutes until cheese is melted and bubbling. Optionally broil for 2 to 3 minutes to achieve extra browning.
07 - Garnish with chopped parsley before serving. Serve hot.