1. In 2-quart saucepan over medium heat, in hot olive oil, cook onion until tender, about 5
minutes. Remove from heat; stir in spinach, cheese, pepper, and egg until mixed.
2. With knife, cut phyllo lengthwise into 2-inch-wide strips. Place strips on waxed paper, then cover with slightly damp paper towels to prevent phyllo from drying out.
3. Place 1 strip of phyllo on work surface; brush top lightly with melted butter or margarine. Place about 1 teaspoonful spinach mixture at end of strip. Fold one corner of strip diagonally over filling so that the short edge meets the long edge of strip, forming a right angle. Continue folding over at right angles until you reach the end of the strip to form a triangular package. Place package, seam side down, in 15 1/2" by 10 1/2 jelly-roll pan; brush with butter or margarine
4. Repeat with remaining phyllo strips and spinach mixture. If not serving right away, cover with foil and refrigerate.
5. About 25 minutes before serving, preheat oven to 425°F. Bake pastries 15 minutes or until golden.