1. Heat up the oil in a 12 inch cast iron skillet. Add the potato slices to the skillet and cook over medium heat, turning once in a while until the potatoes are tender and slightly golden, about 10 minutes. Remove potatoes from the skillet and set aside.
2. Add the onion and garlic to the skillet and cook, stirring occasionally until the onions have become transparent. Remove from skillet and spread over the potatoes. Add about ¼ teaspoon of salt to the potatoes.