Peel and chop the potatoes into evenly sized pieces. Place them in a large pot and cover with cold water. Add a generous pinch of salt.

Bring to a boil over medium-high heat and cook for 15-20 minutes, or until the potatoes are fork-tender.

Preheat your oven to 425°F (220°C).

Line a baking sheet with parchment paper for easy cleanup and even baking.

While the potatoes cook, melt the butter in the microwave or on the stovetop.

Warm the cream gently in a microwave-safe bowl or small saucepan. Set both aside.

Drain the potatoes thoroughly and return them to the pot over low heat. Stir briefly to evaporate any remaining moisture.

Mash the potatoes using a ricer, masher, or food mill until smooth and lump-free.

Add 2 tablespoons of melted butter, warm cream, Parmesan cheese (if using), salt, and pepper to the mashed potatoes. Stir until fully combined.

Mix in the egg yolks, ensuring the mixture is smooth and creamy.

Transfer the potato mixture to a piping bag fitted with a large star tip.

Pipe small swirls or rosettes onto the prepared baking sheet, spacing them about 1 inch apart.

Brush the tops of the potato swirls with the remaining melted butter.

Bake in the preheated oven for 15-20 minutes, or until the edges are golden brown and slightly crispy.

Remove the Duchess Potatoes from the oven and garnish with fresh chopped chives or parsley.

Sprinkle with a pinch of sea salt for a finishing touch. Serve immediately and enjoy!