1/2 lb. Italian sweet sausage, casing removed
1 c. chopped fresh mushrooms
1/2 c. chopped onion
1 c. pizza sauce
4 oz. Mozzarella cheese, cut into 1/4 inch cubes
2 tbsp. Parmesan cheese
1 (17 1/4 oz.) pkg. Pepperidge Farm frozen puff pastry sheets
1 egg, beaten with 1 tsp. water

Brown sausage in a skillet over moderately high heat; drain and discard fat. Add mushrooms and onion and cook, stirring until tender. Remove from heat and stir in pizza sauce, Mozzarella, and Parmesan cheeses. Set aside to cool. Thaw pastry 20 minutes; unfold. On a lightly floured surface, roll each sheet to a 12 inch square; cut each into 16 (3 inch) squares. Top each square with some of the sausage mixture. Brush edges of pastry with egg mixture; fold in half to form triangles. Press edges together with the tines of a fork. Brush with more egg; transfer to ungreased baking sheets and bake at 400 degrees for 8 to 10 minutes or until golden brown and puffed. Makes 32 hors d'oeuvres.