**Preheat the Oven:**
- Preheat your oven to 375°F (190°C). Lightly grease a muffin tin with non-stick cooking spray.
**Prepare the Mixture:**
- In a mixing bowl, whisk the eggs, then stir in mashed potatoes, cheddar cheese, Parmesan cheese, sour cream, green onions, and seasonings. Mix until well combined.
**Fill the Muffin Tin:**
- Spoon the potato mixture into the prepared muffin tin, filling each cup about ¾ full. Smooth the tops with the back of a spoon.
**Bake:**
- Bake in the preheated oven for 25-30 minutes, or until the tops are golden brown and the edges are crispy.
**Cool and Serve:**
- Allow the puffs to cool in the tin for 5 minutes before carefully removing them. Serve warm with sour cream, ketchup, or your favorite dipping sauce.