Prepare to create these delightful Mashed Potato Cheese Puffs by following these simple steps:

1. Prepare Mashed Potatoes: If using leftovers, ensure they are well-mashed and smooth with no lumps.
2. Mix Dry Ingredients: In a large bowl, whisk together the flour, baking powder, garlic powder, onion powder, salt, and pepper.
3. Combine the Mixtures: Add the mashed potatoes to the dry ingredients and mix well.
4. Add Egg: Crack the egg into the mixture and stir until fully incorporated.
5. Incorporate Cheese: Fold in the shredded cheese and add green onions if you desire. Ensure everything is well combined.
6. Shape the Puffs: Using your hands, form small balls (about the size of a golf ball) from the mixture.
7. Heat the Oil: In a frying pan, pour enough oil to submerge halfway and heat it over medium heat.
8. Fry the Puffs: Once the oil is hot, gently place a few potato balls in at a time. Fry until they are golden brown, about 3-4 minutes per side.
9. Drain: Use a slotted spoon to remove the puffs from the oil and place them on a paper towel to drain excess oil.
10. Serve Warm: Once drained, enjoy the Mashed Potato Cheese Puffs right away for maximum deliciousness.

Following these steps ensures that your cheese puffs come out perfectly crispy on the outside and cheesy on the inside!