Total time: 1 hour, 40 minutes
Note: From Russ Parsons. You can use either the dark-skinned sweet potatoes commonly referred to as yams, or the lighter-skinned type.
1 (1-pound) sweet potato
Butter for lining the ramekins
2 egg yolks
1 tablespoon dark brown sugar
2 teaspoons grated orange zest (about 1 large orange)
2 tablespoons ( 1/4 stick) butter, softened
1/4 teaspoon salt
4 egg whites
1/8 teaspoon cream of tartar
1/4 cup chopped toasted hazelnuts
1. Heat the oven to 375 degrees. Put the sweet potato on a cookie sheet and bake until a knife easily pierces the meat to the center, about 1 hour. Meanwhile, generously butter six (one-half cup) straight-sided ramekins or individual soufflé molds. Remove the sweet potato from the oven and set aside until cool enough to peel.
2. Peel the sweet potato and cut it into chunks. Purée it in a food processor with the egg yolks, brown sugar, orange zest, butter and salt until the mixture is smooth. If necessary, stop and scrape down the sides of the work bowl and continue puréeing. This makes about 2 cups purée.
3. Divide the mixture evenly among the six buttered ramekins. Tap firmly on the counter to settle the mixture evenly. (The recipe can be prepared ahead to this point and refrigerated tightly covered.)
4. Beat the egg whites using a portable or stand mixer until frothy. Add the cream of tartar and continue beating until stiff peaks form. The egg whites will be ready when they form well-defined pointed peaks that stand straight up and retain their shape, several minutes.
5. Sprinkle the chopped hazelnuts over the egg whites and gently fold them in. Divide the egg white mixture evenly among the ramekins, spooning them in a soft mound over the sweet potato mixture. Shake the ramekins gently from side to side to distribute the egg whites evenly.
6. Place the ramekins on a cookie sheet and bake until the tops are puffed and golden brown in spots, 18 to 23 minutes. A sign of doneness is when the soufflé becomes extremely fragrant. Don't over-bake, or the center will be dry. Remove from the oven; serve immediately.
Each serving: 179 calories; 5 grams protein; 22 grams carbohydrates; 3 grams fiber; 8 grams fat; 3 grams saturated fat; 78 mg. cholesterol; 144 mg. sodium.