Cut the potatoes into 1/2-inch cubes and soak them in a bowl of cold water. If using Yukon gold or other thin-skinned varieties, peeling is optional. After soaking, drain and pat dry with a clean kitchen towel.

Peel and slice the onion thinly.

Heat a cast iron skillet or heavy frying pan over medium heat and pour in the oil.

Once the oil is hot and shimmering, add the potatoes in a single layer.

Allow the potatoes to cook without stirring for about 3 minutes. Then stir and continue to cook for an additional 6-8 minutes, stirring every 2 minutes, until the potatoes are mostly golden brown on all sides.

Add the sliced onions and season with salt and pepper. Stir until the potatoes and onions are well mixed.

Reduce the heat slightly and cook for another 5 minutes or until the onions are softened and caramelized. Serve warm.