Preheat your oven to 400°F (200°C) and lightly grease a muffin tin to prevent sticking.
Mix the wet ingredients: In a large bowl, whisk the eggs and sour cream together until smooth. This ensures the mashed potato mixture has a light, creamy consistency.
Add the cheeses: Stir in the shredded cheese, Parmesan cheese, and chopped chives. Make sure everything is evenly distributed before moving to the next step.
Season and mix the potatoes: Gently fold the mashed potatoes into the egg mixture. Mix everything thoroughly but carefully to avoid breaking down the potatoes too much.
Prepare to bake: Spoon the mixture into the muffin tin, filling each cup about three-quarters full. This will allow the puffs to rise slightly during baking.
Bake until golden: Place the tin in the oven and bake for about 20–25 minutes, or until the tops are golden brown and puffed up.
Cool and serve: Allow the puffs to cool slightly before removing them from the muffin tin.
Enjoy your crispy and cheesy Mashed Potato Puffs with your favorite dip or as a side for your main course!