You can use a mix of dense, waxy potatoes like chaleurs and floury russets for this hearty mash.
- 2 lb. waxy potatoes
- 1 lb. russet potatoes
- 12 cloves garlic, peeled and crushed
- 1 cup buttermilk
- 1⁄4 cups heavy cream
- 10 Tbsp. butter
- 1⁄2 tsp. chopped fresh winter savory
- 1⁄2 bunches chopped chives
- Sea salt and freshly ground pepper to taste
Put peeled potatoes and crushed garlic cloves into a large pot of cold water and gently boil over medium heat until tender, about 40 minutes. Reserve 1⁄2 cup of the potato cooking water and drain potatoes and garlic in a colander.
Preheat oven to 425°. Bring the buttermilk and heavy cream to a simmer in a saucepan over medium heat (mixture will separate and look curdled), and then set aside.
Return potatoes and garlic to a large pot over medium-low heat and season to taste with sea salt and pepper. Pour in three quarters of the hot buttermilk and cream and mash potatoes coarsely with a potato masher. Thin mashed potatoes with remaining hot buttermilk and some of the reserved cooking water, if you like.
Stir in 6 tbsp. of the butter, fresh winter savory and chives. Adjust seasonings.
Divide mashed potatoes between 4-6 individual gratin dishes or 1 large baking dish and drizzle with remaining 4 tbsp. melted butter. Transfer to oven and bake until lightly browned, about 20 minutes.