Because potatoes are denser and cook more slowly than eggs, you need to precook them to ensure they are done when the eggs are ready. Boil the potatoes before you pan fry them with the eggs. The key in parboiling the potatoes is cooking them long enough so they become soft, but not so long that they fall apart when you pan fry them.
Cube the potatoes uniformly. The size of the cubes does not matter as long as they are roughly the same size so they will cook evenly.
Fill a large pot with water and a pinch of salt. Bring the water to a boil.
Add the cubed potatoes to the boiling water. The water will stop boiling.
Bring the water back to boiling and let the potatoes boil for five minutes. Reduce the heat to medium.
Stir the pot with the slotted spoon and remove one potato cube as a tester.
Transfer the potato cube to a plate and cut it with the spoon. The potato should cut easily with a little resistance. You also can let the potato cool and bite into it. Discard or eat the tester. If the potato does not cut easily, simmer the rest of the potatoes for one minute and test again.
Drain the potatoes in a colander. Run cold water over the potatoes to stop them from cooking. Drain the potatoes before you pan-fry them with eggs.