Add spinach, and gently saute until wilted, about 2 minutes. Transfer to a clean kitchen towel or paper towels, and wring out as much liquid as possible. Finely chop spinach, and transfer to a bowl. Add remaining ingredients, and stir well to combine.
Fill a large skillet with about 1/2 inch oil. Place over medium heat until oil is almost smoking. (To test, drop a small bit of batter into the skillet; it should sizzle upon contact.)
Working in batches so as not to crowd skillet, carefully spoon about 2 tablespoons batter into oil for each latke. Lightly tamp down to flatten. Cook, turning once, until golden on each side, 2 to 3 minutes. Using a slotted spatula, transfer to a paper-towel-lined wire rack to drain. Repeat with remaining batter. Serve immediately with sour cream and applesauce.