1. For 2 minutes over medium-high heat, heat a very big (12-14 inch) nonstick skillet. Pour in the olive oil.
2. Put in the sliced onions. Using a bit of Kosher salt and a pinch of black pepper, season the onion slices. Cook, making sure to stir periodically, for about 5 minutes, or until golden. Reduce the heat to a medium setting.
3. In a medium bowl, whisk together the eggs, ½ teaspoon of Kosher salt, a pinch of black pepper, and 2 tablespoons of Parmesan cheese while the onion is frying. Set this aside.
4. Add the spinach leaves to the skillet when the onions are golden brown. Cook, stirring constantly, for about 1 minute, or until the spinach begins to wilt.
5. Fill the skillet with the egg mixture. Cook them over medium heat, ensure to move them around with a rubber spatula until they are set to your preference. Red pepper flakes can also be added as a finishing touch. Serve right away and enjoy.

This recipe makes for a delicious and healthy meal, and you can enjoy it as desired with your family. The entire recipe can be made in a total of 20 minutes, including a prep time of 10 minutes and a cook time of 10 minutes.

If you would like more ways to cook your spinach with eggs, then try watching this video recipe.