Peel and chop the potatoes into even chunks. Place them in a large pot filled with salted water over high heat and boil for 15-20 minutes until fork-tender. Drain well.

Preheat your oven to 425°F (220°C) and line a baking sheet with parchment paper.

Melt 2 tablespoons of butter in a small saucepan over low heat. Warm the heavy cream in a separate container until heated but not boiling.

Mash the drained potatoes in a mixing bowl until smooth. Stir in melted butter, warm cream, grated Parmesan, salt, black pepper, and egg yolks until thoroughly mixed.

Scoop the potato mixture into a piping bag and pipe small mounds into spirals on the baking sheet, keeping them about 2 inches apart.

Brush the tops of the swirls with the remaining melted butter. Bake for 15-20 minutes until golden brown and crispy.

Remove from oven, let cool slightly, garnish with chives or parsley, and sprinkle with sea salt before serving warm.