Start by washing and drying your potatoes. Slice them into ¼ inch rounds. If you prefer, you can peel them, but leaving the skins on adds a lovely texture. Thinly slice the onion so that you have about 1 cup.
In a large skillet, heat the cup of vegetable oil over medium heat. You want the oil hot enough that it sizzles when you add the potatoes, but not so hot that it smokes.
Once the oil is ready, add the sliced potatoes to the skillet in a single layer. Make sure not to overcrowd the pan, as this will steam the potatoes instead of frying them. Fry for about 5-7 minutes on one side until they are golden brown.
Carefully flip the potatoes over using a spatula, then add the sliced onions to the skillet. Sprinkle with salt, black pepper, and garlic powder. Stir gently to combine and ensure the onions are distributed evenly.
Cook for an additional 5-10 minutes, stirring occasionally, until the potatoes are cooked through and the onions are caramelized. You want the potatoes to be tender on the inside and crispy on the outside.
Once the potatoes and onions are cooked to your liking, use a slotted spoon to transfer them to a plate lined with paper towels to drain any excess oil. If desired, sprinkle with fresh chopped chives for garnish before serving.