Serves 12

4 pounds sweet potatoes

2 pounds carrots

5 cups water

2 tablespoons sugar

1 stick unsalted butter

Kosher salt and freshly ground black pepper

1 cup plain yogurt

1 teaspoon freshly grated nutmeg

¼ teaspoon ground cayenne pepper

1. Bake: Scrub potatoes. Cut a slit in each. Set on the center rack of 375-degree oven. Bake until tender when squeezed, about 1 hour.

2. Boil: Peel and trim carrots. Cut into 1-inch lengths. Tumble into a big saucepan. Pour in water, sugar, 2 tablespoons butter, salt and pepper. Set over medium heat. Bring to a boil, cook uncovered until water has evaporated and carrots begin to sizzle in the butter, about 30 minutes.

3. Swirl: Scrape out flesh of sweet potatoes and combine with carrots in food processor. Add remaining butter, the crème fraiche, nutmeg and cayenne. Process very smooth.

Provenance: Adapted from The Silver Palate