Preheat your oven to 375°F (190°C).
In a mixing bowl, combine mashed potatoes, shredded cheese, eggs, milk, and green onions.
Season the mixture with salt and pepper, then mix until well combined.
Grease a muffin tin and spoon the mixture evenly into the cups.
Bake for 20-25 minutes or until golden and puffed.
Allow to cool for a few minutes before serving.