Spinach Phyllo Pie

2 pounds fresh spinach
1 package fresh mushrooms
1 large onion
5 egg whites
8 ounces cheddar cheese, grated
8 ounces mozzarella cheese, grated
1 teaspoon pepper
1 box phyllo dough

Remove stems from spinach, wash and drain. Cut onions and saute in water until tender. Wash and slice mushrooms and add to the onions (cook until all water evaporates), remove onions & mushrooms from heat and put in a large bowl. Saute spinach in water tossing frequently until all liquid evaporates. Mix onions/mushrooms & spinach together in bowl & make sure onions and mushrooms are evenly distributed throughout the spinach. Beat egg whites lightly, add grated cheese to egg mixture and mix thoroughly. Add spinach mixture to egg and cheese mixture and stir until well mixed.

Quickly layer 5-7 sheets on the bottom of the dish spraying each layer lightly with Pam. Then put on half of your spinach mixture. Put another 5-7 sheets of phyllo. Then the last of your spinach mixture. Top with 10 to 15 sheets of phyllo, sprayed lightly with Pam between each layer. Trim any excess dough around the edge, then moisten your fingertips and seal around the edges like a normal pie crust. Brush top with butter or PAM. Use a sharp knife to cut through the entire top layer in the pattern you will cut after baking. Bake in 400-425 degree oven for 30 minutes.