Cook ground beef and chopped onion in a skillet until beef is no longer pink. Drain well.

Dissolve beef bouillon cubes in boiling water and stir into the meat mixture.

Add shredded cheddar cheese, sliced fresh mushrooms, diced celery, grated Parmesan cheese, dill weed, dried thyme, crushed dried rosemary, salt, and pepper to the meat mixture and mix well.

Prepare pie crusts according to package directions.

Divide dough into four portions and roll each into a 14-inch square on a floured surface.

Cut each square into four 7-inch squares.

Place a scant 1/2 cup of meat mixture in the center of each square.

Moisten edges of pastry with water and fold over filling, forming a triangle.

Press edges with a fork to seal.

Make a 1-inch slit in the top of each triangle.

Place on ungreased baking sheets.

Beat egg and water together and brush over the pastry.

Bake at 375°F (190°C) for 30-35 minutes, or until golden brown.