01 - Preheat your oven to 400°F. Lightly grease a baking sheet or line it with parchment paper for easy cleanup.
02 - If starting from raw potatoes, peel and boil 3 medium potatoes until tender. Drain thoroughly and mash with 2 tablespoons butter and 1/4 cup milk. Season with salt and pepper, then allow to cool slightly. If using leftover mashed potatoes, simply warm them slightly for easier mixing.
03 - In a large mixing bowl, combine the mashed potatoes with shredded cheddar, grated Parmesan, beaten eggs, chopped chives, smoked paprika, and flour. Mix thoroughly until all ingredients are evenly distributed and the mixture is smooth and cohesive.
04 - Using a spoon or small ice cream scoop, portion the mixture into 12 equal mounds on the prepared baking sheet. Space them about 2 inches apart to allow for even cooking and slight expansion.
05 - Brush the tops of each puff generously with the melted butter. This step promotes even browning and creates a beautifully golden, appetizing crust.
06 - Place the baking sheet in the preheated oven and bake for 25 to 30 minutes. The puffs are done when they achieve a deep golden-brown color, appear puffed and set, and feel firm to the touch.
07 - Remove from the oven and allow the puffs to cool on the baking sheet for 3 to 5 minutes. This brief resting period helps them set slightly for easier handling. Serve warm, optionally accompanied by sour cream for dipping.