# 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
# How to Make It:
01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper. Toss potato slices with olive oil, salt, and pepper. Arrange in a single layer on the sheet and roast for 25 to 30 minutes, turning once, until golden and tender.
02 - While potatoes roast, melt butter and olive oil in a large skillet over medium-low heat. Add onions and salt, cooking gently for 25 to 30 minutes until deeply golden and caramelized. Stir in thyme and balsamic vinegar, cook 1 to 2 minutes more, then remove from heat.
03 - Reduce oven temperature to 400°F. Lightly grease a baking dish and arrange roasted potato slices overlapping slightly. Evenly spread caramelized onions over potatoes. Sprinkle Gruyère and Parmesan cheeses on top.
04 - Bake for 10 to 15 minutes until cheese is melted and bubbling.
05 - Allow to cool slightly. Garnish with fresh parsley and serve warm.