Cut the potatoes into small cubes. Split the leek lengthways and wash. Then divide the halves lengthways again and cut across into short strips.
In a pan with a lid, heat the fat and sauté the onions. Add the potato cubes and fry, turning several times. Roasted aromas can develop. Pour in the leek and keep stirring / turning. If the potatoes still have too much bite, put the lid on and finish cooking at a low temperature. Salt as needed.
The potato pan can be eaten as a main course or as a side dish.
Note: The cooking time depends on the size of the potato cubes.