Begin by peeling and chopping 2 pounds of Russet or Yukon Gold potatoes into even-sized chunks. Place them in a large pot filled with salted water and bring it to a boil. Cook for 15-20 minutes or until the potatoes are fork-tender; you should be able to easily pierce them with a fork. Drain the potatoes thoroughly and let them steam for a minute.

While the potatoes are draining, preheat your oven to 425°F (220°C). Prepare a baking sheet by lining it with parchment paper, ensuring each surface is covered to prevent sticking.

In a separate small saucepan or microwave-safe dish, melt 4 tablespoons of unsalted butter and warm 1/2 cup of heavy cream until just heated through. Be careful not to boil the cream. Set this mixture aside as it will be combined later.

Once the potatoes have drained completely, return them to the pot over low heat. Mash them using a potato masher until smooth and fluffy. Mix in the melted butter, warmed cream, 1/2 cup of grated Parmesan cheese, and season with salt and pepper to taste. Incorporate 2 egg yolks until the mixture is fully combined and creamy.

Transfer the creamy potato mixture into a piping bag fitted with a star tip. If you don’t have a piping bag, a zip-top bag with a corner snipped off will also work. Pipe the mixture onto your prepared baking sheet in small mounds, creating elegant rosettes.

Brush the piped Duchess Potatoes with any remaining melted butter for a golden finish. Place the baking sheet in the preheated oven and bake for 15-20 minutes or until the edges are golden brown and crispy.

Once baked, remove the Duchess Potatoes from the oven and sprinkle them with chopped fresh chives or parsley for a vibrant touch. Finish with a light dusting of sea salt for added flavor. Serve immediately while still warm.