Potato and Celery Root Mash
From: bonappetit.com
SERVES 6-8
2 1/2lb mixed russet, Yukon Gold, and white-skinned potatoes, peeled, cut into 2” cubes
1lb celery root (celeriac), peeled, cut into 3/4” cubes
6” piece of horseradish, peeled, coarsely grated
1 1/2 cups sour cream
3 tablespoons Dijon mustard
2 tablespoons (1/4 stick) unsalted butter
Kosher salt
Place potatoes, celery root, and horseradish in a large pot. Add water to cover by 1”. Bring to a boil, reduce heat to medium-high, and simmer until vegetables are tender, 25–30 minutes.
Drain, reserving 1 cup cooking liquid. Return vegetables to pot; add sour cream, Dijon mustard, and butter. Using a potato masher, coarsely mash vegetables. Add reserved cooking liquid by tablespoonfuls if mash is too stiff. Season to taste with salt.