# What You'll Need:
→ Potatoes
01 - 4 large Yukon Gold potatoes, scrubbed and sliced into ½-inch rounds
02 - 2 tbsp olive oil
03 - ½ tsp kosher salt
04 - ¼ tsp black pepper
→ Caramelized Onions
05 - 2 large yellow onions, thinly sliced
06 - 2 tbsp unsalted butter
07 - 1 tbsp olive oil
08 - ½ tsp sugar
09 - ¼ tsp salt
10 - 1 tsp fresh thyme leaves or ½ tsp dried thyme
→ Topping
11 - 1 cup (100 g) Gruyère cheese, grated
12 - 2 tbsp fresh parsley, chopped (optional)
# How to Make It:
01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, toss potato slices with olive oil, kosher salt, and black pepper. Spread in a single layer on the prepared baking sheet and 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 sliced onions and salt, cooking while stirring often for 10 minutes until softened. Add sugar and thyme and continue cooking, stirring occasionally, for 20 to 25 minutes until deeply golden and caramelized, reducing heat as necessary to avoid burning.
04 - Remove roasted potatoes from the oven and arrange them in an ovenproof shallow baking dish or skillet, slightly overlapping the slices.
05 - Evenly spread the caramelized onions over the potatoes, then sprinkle grated Gruyère cheese on top.
06 - Return the assembled 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 a golden brown crust.
07 - Garnish with chopped fresh parsley if desired and serve hot.