Preheat your cast iron skillet on medium heat. Be sure to add a nice helping of your favorite high heat cooking fat. You want to make sure your skillet is nice and hot when you add your potatoes.
With your sharp knife, finely dice your potatoes into roughly equal pieces about ¼ inch cubes.
When you cast iron is nice and hot, add your potatoes to the skillet. Season generously with salt, pepper and garlic.
Add a lid to your pan and let the potatoes cook for at least 10 minutes with the lid on. Cooking with the lid on will allow the pan to create a crust on the bottom surface of the potatoes while the lid traps the moisture and cooks the potatoes partially by steam.
After 10 minutes, flip the potatoes using a metal spatula. Using a metal spatula allows you to scrape the bottom of the pan efficiently. Just be careful not to stir the potatoes too much. Over stirring will cause the soft potatoes to clump and not cook as well.
If the bottom of the pan looks dry, add some more cooking fat to the skillet. Replace the lid after flipping the potatoes and continue to cook until your desired doneness.
Serve with sides or in a breakfast bowl immediately.