Prep the Potatoes: Peel and dice the potatoes into evenly sized pieces for consistent cooking.
Cook the Potatoes: Heat butter or olive oil in a large skillet over medium heat. Add diced potatoes (and onion, if using) and cook, stirring occasionally, until tender and golden brown, about 15–20 minutes.
Add the Cheese: Sprinkle shredded cheese over the cooked potatoes. Cover the skillet for 2–3 minutes until the cheese melts.
Season and Serve: Season with salt and pepper to taste. Garnish with chopped parsley if desired. Serve hot as a comforting side or a simple meal.
Serving and Storage Tips
