Preheat oven to 400F. Grease a muffin pan and set aside.
In a medium size skillet, cook bacon. Once crispy, remove bacon from pan and set on a paper towel to soak up excess grease. Once slightly cooled, chop bacon.
In a large bowl, combine mashed potatoes, eggs, cheddar cheese, bacon and chives. Season with salt and pepper.
Scoop spoonfuls into each cup.
Sprinkle each potato puff with Parmesan cheese.
Bake for 30-35 minutes until golden brown.
Cool for 5 minutes. Garnish with sour cream and chives. Serve warm.