4poundsrusset potatoespeeled and cut into 2-inch pieces
1½teaspoonskosher saltplus more for boiling potatoes
1cupto 1¼ cups whole milkheated
3tablespoonsunsalted butter
5.2ounces(1 package) Boursin cheese
Fresh herbs for garnish(parsley, thyme, or chives if desired)
Instructions
Place potatoes in a large pot, cover with cold water by 2 inches and add a teaspoon or so of kosher salt. Bring to a boil, then reduce to a simmer. Simmer until fork-tender but not falling apart, about 30 minutes; drain.
Just before the potatoes are done, heat milk (on the stove or in the microwave) with the butter, just until the butter is melted and milk is warm.
Transfer potatoes to a large mixing bowl or mixer with the whisk attachment. Mash, then beat (with a hand mixer, or stand mixer) on medium speed until finely crumbled.
Add 1 cup milk, butter, 2 teaspoons salt, and Boursin cheese. Beat until very smooth. Add up to ¼ cup milk if needed to create a light, creamy texture. Serve hot, garnished with fresh herbs if desired.