1. In a frying pan, add plenty of sunflower oil and fry the potatoes in 2 batches. Let them lightly brown and place them in a baking dish. Season with salt and pepper.
2. Fry the onions and place them over the potatoes, after draining them well. Place them over the potatoes and add the butter in small pieces.
3. Bake in a preheated oven at 180°C until golden brown.
