Greek spinach triangles

1 c  butter; or margarine*
      1 pk Phyllo pastry
      2    Eggs; beaten
      1    Onion; finely chopped
      8 oz Cream cheese; cut in chunks
    1/4 ts Pepper
    1/2 lb Feta cheese
     20 oz Frozen chopped spinach
 
  * To cut calories, you may use butter-flavored cooking spray in place
  of the butter.
   Cook spinach according to directions and drain well. Mix all
  ingredients except butter and pastry. Refrigerate mixture at least 1
  hour.
   Open package of dough and cut a strip 2" wide, cutting through all
  layers. Cover remaining dough with a damp cloth to keep from cracking.
   Separate dough so that you have 2 sheets for each triangle. Brush the
  dough with melted butter and put 1 rounded teaspoon spinach mixture
  at the top of the strip. Fold pastry over like folding a flag. Place
  on well-buttered baking sheet and brush top with butter. Bake at 375
  deg. for 20 min. Serve warm.
   To freeze the triangles before cooking, butter both sides of
  triangle and wrap well. Bake when needed.