Sweet Potato Soufflé

INGREDIENTS

• 2 pounds sweet potatoes
• 1 tablespoon unsalted butter
• 3 tablespoons sugar
• ¼ cup mild honey, such as clover
• ½ teaspoon ground cinnamon
• ¼ teaspoon freshly grated nutmeg
• ⅛ teaspoon salt
• ¼ teaspoon ground ginger
• ¼ cup plain low-fat yogurt
• 2 teaspoons freshly squeezed lime juice
• 8 egg whites, at room temperature
• ⅛ teaspoon cream of tartar

PREPARATION

1. Preheat the oven to 425ºF. Scrub the sweet potatoes and pierce in several places with a sharp knife. Line a baking sheet with foil and place the potatoes on top. Bake for 45 minutes to an hour, depending on the size of the potatoes, until thoroughly soft and beginning to ooze. Remove from the heat and let cool.
2. Adjust the rack to the lower third of the oven and turn the oven down to 400ºF. Rub the inside of a 2-quart soufflé dish or six 1- or 1 1/2-cup soufflé dishes with butter and dust with 2 tablespoons of the sugar, tilting the dish to coat evenly.
3. Peel the potatoes and puree in a food processor fitted with the steel blade. Add the honey, cinnamon, nutmeg, salt, ginger, yogurt, and lime juice and mix together well.
4. Begin beating the egg whites at medium speed in a standing mixer fitted with the whisk attachment or with an electric beater. When they begin to foam, add the cream of tartar. When soft peaks begin to form, slowly add the remaining tablespoon of sugar while beating and continue to beat until the egg whites form stiff but not dry peaks. Stir one fourth into the sweet potatoes, and gently fold in the remainder. Scrape into the soufflé dish (or dishes). Place on a baking sheet and bake a large soufflé for 20 to 25 minutes, small soufflés for 15 minutes, or until puffed and just beginning to brown. Serve at once. The soufflé should be runny on the inside.