Good Eats' root vegetable gratin

Paulette Bruce
Good Eats, Sacramento

Pick up a trick from the pros and use a mandoline—with a finger guard for safety—to slice the root vegetables for this rich, creamy gratin. It's quick and also the easiest way to produce consistent-sized slices that will cook at the same rate.

Ingredients

2 cups heavy cream
1 cup whole milk
2 bay leaves
5 sprigs thyme
8 sage leaves
Pinch of grated nutmeg
2 tsp. kosher salt
1/2 tsp. freshly ground white pepper
Butter for greasing a casserole
3 parsnips (1/2 lb.)
2 russet potatoes (1 lb.)
1 sweet potato (3/4 lb.)
1 celery root (3/4 lb.)
1 red onion, finely chopped
1/4 cup all-purpose flour

Directions

Place cream and milk in a medium saucepan with bay leaves, thyme, sage, nutmeg, salt and white pepper and bring to a simmer over medium heat. Remove from heat and let steep for 1/2 hour, then strain (may be refrigerated up to 1 day).

Preheat oven to 350 degrees. Butter a 2 1/2-quart gratin dish. Peel parsnips, potatoes, sweet potato and celery root and place in a bowl of cold water. Slice vegetables thinly using a mandoline or similar slicer. Alternate layers of sliced root vegetables in the casserole with onion, flour and cream mixture, lightly seasoning each layer with salt and white pepper. Adjust the amount of cream, if necessary, so that vegetables are just standing in cream. Cover snugly with foil. Bake 1 hour, uncover and bake 20 minutes more, until golden. Let rest 30 minutes before serving.

Serves 4