Peel the potatoes and cut them into chunks.

Cook the potatoes for about 25 minutes, or until fork tender.

Preheat the oven to 400 degrees Fahrenheit and prepare a baking tray with nonstick spray.

Once the potatoes are cooked, drain them and cook off any remaining water for about 5 minutes over low heat. Place the cooked potatoes in a medium-sized bowl.

Add heavy cream, salt, pepper, and 2 tablespoons of butter to the potatoes. Mash the potatoes until smooth.

Add the egg yolks and mash some more, being careful not to overwork the mixture.

Put the mashed potatoes in a piping bag fitted with a star tip. Pipe the potatoes onto the prepared baking sheet in a swirl.

Melt the remaining butter in the microwave for 20-30 seconds and brush it onto the potatoes.

Bake in the oven for 25-30 minutes or until golden brown.