The herbs are in the boursin cheese; just stir the cheese into the potatoes and bake. Or prepare, cover, and refrigerate the side dish casserole up to 24 hours ahead of serving time.
Cover potatoes with boiling water. Cook, covered, for 20 to 25 minutes or until tender. Drain; return potatoes to pan. Mash with potato masher or beat with mixer on low speed until smooth. Add cheese; beat until combined. Beat in milk until combined. Season with salt and pepper. Transfer to a 2-quart casserole; cover.
Bake in a 350 degree F oven for 25 minutes or until heated through. (Or, cover and chill up to 24 hours. To reheat, bake, covered, in a 350 degree F oven for 1-1/2 hours or until heated through.) Makes 8 to 10 servings.