01 - Preheat oven to 400°F. Lightly grease baking sheet or line with parchment paper.
02 - If not using leftovers, peel and boil potatoes until tender. Mash with 2 tablespoons butter and milk until smooth. Season with salt and pepper. Allow to cool slightly.
03 - In large bowl, mix mashed potatoes with cheddar, Parmesan, eggs, chives, smoked paprika, and flour. Blend until completely smooth and well incorporated.
04 - Use spoon or small ice cream scoop to portion 12 evenly sized dollops onto prepared baking sheet, spacing apart for even baking.
05 - Brush tops of each puff with melted butter to promote golden browning.
06 - Bake for 25 to 30 minutes until puffs are golden brown and set throughout.
07 - Let cool on baking sheet for several minutes before transferring. Serve warm, optionally topped with sour cream.