Cut the potatoes into 1/2-inch cubes (skin can be left on if thin and well scrubbed).

Add potatoes to a pot and cover with cold water by 1 inch. Add 1/2 tsp salt.

Bring to a boil and cook for 1 to 2 minutes.

Drain in a colander, shaking off excess water. Let sit over the pot for 5 to 10 minutes to dry.

Heat 1 tbsp olive oil in a 12" cast iron skillet. Cook the onion with a pinch of salt until golden, about 5 minutes. Remove to a bowl.

Add the remaining 1 tbsp olive oil to the skillet. Add the potatoes and 1/2 tsp salt, tossing well to coat. Spread in a single layer.

Cook without stirring for 7 to 8 minutes, until the bottom is browned and crisp. Stir and cook the other side, about 15 minutes total.

Add garlic powder, paprika, and pepper. Toss until fragrant.

Stir the onion back in. Sprinkle with parsley and serve warm.