Step 1

Place the sliced potatoes and 1 teaspoon of the salt in a medium saucepan and cover with cold water by about an inch. Bring to a boil over high heat, then reduce the heat to medium-low and simmer for 4 minutes. Drain the potatoes and set aside to cool slightly. Meanwhile, start cooking the onions.

Step 2

Melt 2 tablespoons of the butter in a 10-inch nonstick frying pan over medium heat. Add the onion and 1/4 teaspoon of the salt, and cook, stirring, until caramelized and lightly browned, about 12 minutes. Transfer the onions to a small bowl and set aside.

Step 3

Melt the remaining 3 tablespoons of butter in the same frying pan over medium-high heat. Add the potatoes and season with pepper and the remaining 1/4 teaspoon salt. Stir to coat with the butter and spread into an even layer. The potatoes will not be in a single layer. Cook undisturbed, until the bottoms are lightly browned, 3 to 4 minutes. Stir the potatoes, and cook, flipping occasionally, until all the potatoes are browned, about 7 minutes more. Return the onions to the skillet, stir to combine, and cook for 2 minutes more. Garnish with the parsley.