Peel and dice potatoes into small cubes. Boil in salted water for 10–12 minutes until fork-tender. Drain well and mash until smooth—no milk or butter added.
While still warm, stir in cheddar, Parmesan, parsley, salt, and pepper. Optional: add garlic powder, paprika, or chili flakes. Let the mixture cool.
Scoop about 1.5 tablespoons of the mixture and roll into balls. For a cheesy center, press a cube of cheese in the middle and seal it inside. Place on a parchment-lined baking sheet.
Melt butter in a small saucepan over medium heat. Add minced garlic and cook for 1–2 minutes until fragrant. Brush each potato bomb with garlic butter.
Preheat oven to 400°F (200°C). Bake for 20–25 minutes until golden and crisp. For extra crunch, roll in breadcrumbs before baking and brush with more garlic butter halfway through.
Serve hot with your favorite dips—try garlic aioli, ranch, spicy ketchup, or creamy sriracha mayo.