Heat air fryer or oven to 400 F. If using the oven, line a baking sheet with foil or oven-safe parchment paper.
In a medium bowl, toss potatoes with oil, salt, pepper, and paprika to taste. Place in air fryer and cook for 21 minutes, tossing every 7 minutes. If using the oven, place potatoes in an even layer on the lined baking sheet and bake for 25-30 minutes or until potatoes are golden and crispy, stirring halfway through.
Meanwhile, in a medium bowl, whisk together eggs, milk, salt, and pepper.
Heat a medium saute pan over medium heat and add butter or oil. Add onions and saute until soft and translucent. Season with salt and pepper and then add spinach. Cook until slightly wilted but not over wilted. Add egg mixture and cook, moving the eggs around occasionally. Take off the heat and set aside.
Place cooked potatoes evenly in bowls, top with eggs, and top with cheese. Serve and enjoy!