Preheat oven to 400°. Wrap 1 sweet potato in aluminum foil, and bake at 400° for 50 minutes to 1 hour or until tender when pierced with fork. Unwrap and cool to room temperature.
Reduce oven temperature to 250°. Peel and grate remaining potatoes with large side of a box grater or grating blade of a food processor. Combine grated potato, eggs, and next 5 ingredients in large bowl. Slip cooked sweet potato flesh out of skin, and stir thoroughly into potato mixture; discard skin.
Heat enough oil in large skillet to cover bottom of pan. Drop batter by tablespoonfuls in hot oil, and fry over medium heat until golden brown and crispy, about 2 to 3 minutes per side. Remove from pan, and place on a baking sheet lined with paper towels to drain. Repeat with remaining latkes, adding more oil to pan if needed. Keep batches of latkes warm in oven on a wire rack placed on a baking sheet. Serve warm with applesauce, soft goat cheese, or sour cream.