Found on:  http://www.nataliemaclean.com/recipes/view/rosemary-mashed-potato-gratin/589

Rosemary Mashed Potato Gratin

 Ingredients
6 medium oblong or yellow-fleshed potatoes (about 3 lbs/1.5 kg)
Salt
1-1/2 cups (375 mL) Milk
1 tsp (5 mL) minced fresh rosemary (or 1/2 tsp/2 mL dried)
1/4 tsp (1 mL) pepper
1-1/4 cups (300 mL) shredded Canadian aged Provolone, Asiago or Gouda cheese, divided

Instructions
Peel potatoes and cut into chunks. In a pot, cover potatoes with cold water; bring to a boil over high heat. Season water with 1 tsp (5 mL) salt. Reduce heat and boil gently for about 15 min or until fork tender. Drain; return pot to low heat for 1 min to dry, shaking often.
Meanwhile, in a saucepan or in a microwave-safe measuring cup, combine Milk, rosemary and pepper. Heat, uncovered, over medium heat on stove-top or on Medium (50%) power in microwave until steaming, for about 3 min.
Preheat broiler. Butter 8 large ramekins or a shallow 8-cup (2 L) baking dish.
Mash potatoes while gradually adding warmed Milk mixture. Mash in 1 cup (250 mL) of the cheese and 1/4 tsp (1 mL) salt, or to taste. Spread into ramekins or baking dish and sprinkle with remaining cheese. Broil for about 3 min or until cheese is browned.