In a large bowl, lightly beat the eggs with a handheld mixer.
Add the mashed potatoes, salt, pepper, garlic, and milk to the eggs. Blend until well combined.
Add in the flour and start off blending slowly, then pick up the speed once most of the mixture has come together.
Fill a large pan with about 1 inch of oil and heat it to the highest temperature. Using a cookie scoop, scoop out mounds of the potato batter and place it into the oil.
Flip the pancakes once they become golden brown. Remove from oil and place on a plate lined with a piece of paper towel to absorb excess oil. Serve warm with sour cream and chopped onions.