Scalloped Potatoes with Caramelized Onions and Gruyere

Ingredients

2 Tbsp olive oil

4 cups thinly sliced onions (sliced crosswise, see how to slice onions)

6 medium-small Yukon gold potatoes (about 1 1/2 pounds), peeled, thinly sliced (1/8-inch thick, it helps to use a mandoline)

3/4 cup grated Gruyere cheese, divided 1/2 cup, 1/4 cup

1/2 cup grated Parmesan cheese

1 teaspoon salt

1/2 teaspoon white pepper (or black pepper if that is what you have)

1 teaspoon of butter to butter the gratin or casserole dish

1/3 cup stock (chicken, beef, or vegetable stock, use vegetable stock for vegetarian option)

1 teaspoon finely minced fresh rosemary

Method