1 large sweet onion
6 tablespoons butter (divided)
2 pounds russet potatoes (or similar baking potatoes)
1 tablespoon extra-virgin olive oil
Kosher salt (to taste)
Freshly ground black pepper (to taste)
Garnish: parsley (fresh minced)
Recipe from The Spruce Eats
1 - Peel the onion, cut it in half lengthwise, and then cut it into thin slices.
2 - Melt 4 tablespoons of butter in a large skillet over medium-low heat. When the foaming subsides, add the onion slices. Cook for about 6 to 8 minutes, or until the onion has softened and browned, stirring frequently. Remove the onion to a plate and set aside.
3 - Meanwhile, peel the potatoes and slice them into rounds between 1/4-inch and 1/2-inch in thickness (about 3/8-inch).
4 - Put the potato slices in a deep, heavy saucepan and cover with water. Bring to a boil over high heat; reduce the heat to medium-low and continue boiling for about 2 minutes. Drain and set aside.
5 - Put the remaining 2 tablespoons of butter and 1 tablespoon of olive oil in the same skillet the onions were cooked in and place over medium to medium-high heat. Add the potatoes to the hot fat and cook for 12 to 15 minutes, or until the slices are browned, stirring and turning frequently. Try to keep the potato slices intact while turning and stirring.
6 - Add the onions back to the pan and heat through. Turn the potatoes out onto a warm serving platter.
7 - Sprinkle with salt and freshly ground black pepper and garnish with chopped fresh parsley.