If spring is all about asparagus and summer is a toss-up between corn and tomatoes, then fall rightly belongs to sweet potatoes—but not just the familiar orange-fleshed variety so obligatory at Thanksgiving. The type known variously as satsuma-imo or Japanese sweet potato (available at Yuno’s Farm at Greenmarket) has a dense, starchy flesh and superb chestnutlike flavor. It’s delicious baked in its skin or cooked in cream, as in the following recipe from Hearth’s Marco Canora.
Marco Canora’s Japanese-Sweet-Potato Gratin
4 pounds Japanese sweet potatoes, peeled
2 quarts (8 cups) heavy cream
5 ounces prosciutto, cut in large dice
1/2 bunch sage, tied with string
Salt and white pepper to taste
Preheat oven to 350. (1) Using a mandoline, slice sweet potatoes about 1/8-inch thick. (2) Place sweet-potato slices in a heavy-bottomed pot and cover with cream. Add prosciutto and sage and season to taste. Simmer over medium heat until tender, about 20 minutes. With a slotted spoon, remove prosciutto and sage and discard. Remove sweet potatoes from pot, reserving one cup of the cream. (3) Layer the potato slices evenly in an 8-by-12 baking dish. Pour the reserved cup of cream over the potatoes and let it settle for 5 minutes. Place baking dish in oven for 15 minutes or until potatoes are golden brown. Serves 6–8.