# Ingredient List:
→ Potatoes
01 - 4 large Yukon Gold potatoes, scrubbed and sliced into ½-inch (1.27 cm) 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)
# Steps:
01 - Preheat oven to 425°F (220°C). Line a baking sheet with parchment paper. Toss potato slices with olive oil, kosher salt, and black pepper in a large bowl. Arrange slices in a single layer on the baking sheet.
02 - Roast potato slices for 25 to 30 minutes, flipping them halfway through, until golden and tender.
03 - While potatoes roast, melt unsalted butter with olive oil in a large skillet over medium-low heat. Add sliced onions and salt, cooking while stirring often until softened, about 10 minutes. Sprinkle in sugar and thyme, then continue cooking, stirring occasionally, until deeply golden and caramelized, about 20 to 25 minutes. Adjust heat if onions brown too quickly.
04 - Remove roasted potatoes from oven and arrange them in a shallow ovenproof baking dish or skillet in slightly overlapping layers.
05 - Evenly spread the caramelized onions over the potatoes. Sprinkle grated Gruyère cheese on top.
06 - Return dish to oven and bake for 10 to 12 minutes until cheese is melted and bubbling. For extra browning, broil for 2 to 3 minutes if desired.
07 - Garnish with chopped fresh parsley if using. Serve hot.