Preheat oven to 400 degrees.

Peel the potatoes. Slice two of them crosswise into rounds about 1/8-inch thick. Slice the third potato lengthwise into rounds about 1/8-inch thick. Spray a large baking sheet with olive oil cooking spray. Place the potatoes in a single layer on the prepared pan and spray with additional cooking spray. Bake for 20 minutes or until golden and crispy, turning the slices once during baking time. While the potatoes are baking, mix the spinach with the cream cheese, eggs, parsley, dill, feta cheese and lemon peel. Season with black pepper to taste.

Remove the potatoes from oven and place the round slices, overlapping them, on the bottom of a 9-inch spring form pan. Place the long slices along the sides. Spoon the spinach mixture into the pan.

Bake the torta for 40 minutes or until the top feels firm and set. Remove the pan from the oven. Release the spring and carefully remove the sides of the pan. Serve hot, warm or at room temperature.