01 - Preheat your oven to 400°F and prepare a baking sheet by greasing lightly or lining with parchment paper.
02 - If starting from raw potatoes, peel and boil 3 medium potatoes until tender. Drain thoroughly, then mash with 2 tablespoons butter and milk until smooth. Season with salt and pepper, then allow to cool slightly.
03 - In a large mixing bowl, combine the prepared mashed potatoes, shredded cheddar, grated Parmesan, eggs, chopped chives, smoked paprika, and flour. Mix thoroughly until all ingredients are evenly distributed and the mixture is smooth.
04 - Using a spoon or small cookie scoop, portion the mixture into 12 evenly-sized mounds on the prepared baking sheet, spacing them about 2 inches apart.
05 - Brush the tops of each puff with the melted butter to promote even browning.
06 - Bake for 25 to 30 minutes until the puffs are golden brown on top and set throughout.
07 - Let the puffs rest on the baking sheet for a few minutes to set. Serve warm, optionally accompanied by sour cream for dipping.