Place the potatoes into a large pot and cover with the chicken broth and water, with an inch of liquid over the potatoes. Bring to a boil over high heat, then cook uncovered until the potatoes are fork-tender, about 20-30 minutes. Drain the potatoes from the pot, then let them steam dry for a minute in the hot pot.
3 lbs Yukon gold potatoes, 4 cups chicken broth
OPTIONAL: While the potatoes cook, melt 2 tablespoons of the butter in a skillet over medium high heat. Add the sliced shallots and a good splash of water. Cover with the lid and let simmer, replacing the water as needed and stirring frequently when you do. This helps break the shallots down quickly. Cook until golden and jammy, about 7 minutes. Set them aside.
8 tablespoon unsalted butter, 2 medium shallots
Pass the drained potato through a potato ricer or food mill (or mash by hand) into the pot or a large mixing bowl.
Stir in the caramelized shallots, add the remaining butter, heavy cream, and lastly, the boursin cheese. Mix gently until well combined. Don't overwork the potatoes or they could become gluey.
5 oz Boursin cheese, ½ cup heavy cream
Taste and season generously with the salt and pepper. Spoon the mashed potatoes into a serving bowl, sprinkle with fresh chives, and serve hot.
2 tablespoon fresh chives, Kosher salt and freshly cracked black pepper