Preheat oven to 425-degrees. Place a large cast-iron or oven proof skillet on the middle rack.
Toss potatoes, 1 tablespoon olive oil, salt and pepper. Transfer potatoes to the hot skillet and arrange in an even layer. Roast for 15-20 mins, or until fork-tender.
Remove the skillet from the oven and add remaining 2 tablespoons of olive oil, onion and garlic. Cook over medium-high heat for 3-4 minutes, or until onions are softened. Stir in spinach, and cook until wilted.
Sprinkle feta over potato mixture, make 5 spaces with a spoon, and crack an egg into each space. Cover and cook over medium heat for 5-7 minutes, until whites are set and yolks are still runny. Sprinke with parsley and serve immediately.
