Heat the skillet: Heat the olive oil in a large skillet over medium heat until it shimmers.

Crisp the potatoes: Add the diced potatoes to the skillet, season with the kosher salt and black pepper, and spread them into an even layer.

Season the base: Lower the heat to medium-low and stir the garlic powder into the potatoes.

Make the wells: Use the back of a spoon to press four small wells into the potato and spinach mixture.

Add the eggs: Crack one egg into each well, being careful not to break the yolks.

Steam the eggs: Cover the skillet with a lid and cook for 3 to 5 minutes, until the egg whites are completely set but the yolks remain soft and runny.

Garnish and serve: Remove the skillet from the heat, sprinkle the crumbled feta cheese evenly over the top, and serve immediately.