In a large heavy-bottomed skillet, like a cast iron skillet, heat 1 tablespoon of avocado oil over medium heat.
Add the onion and sauté until caramelized, about 10 minutes.
Add another tablespoon of oil along with the potatoes. Allow the potatoes to sit on the bottom of the skillet for about 5 minutes before flipping them often to ensure even browning. Continue this process until the potatoes are cooked through, which should take about 20 minutes total. Add the remaining tablespoon of oil, if necessary.
When the potatoes are nearly done, season with garlic powder, salt, and pepper. Serve immediately.