Tuna Pot Pie

pie crust for top & bottom (deep dish)
2 cans mixed vegetables
i medium onion, diced
1/2 cup flour
2 1/2 cups milk
5 T. butter
1 cup water
1 t. salt
1/4 t. pepper
1 package onion soup mix
2 large cans tuna
1 can golden mushroom soup
1 beaten egg

In 4 quart saucepan, cook onion and butter over med. heat until onions are tender and limp.  Stir in flour for about 1 min, gradually start pouring in milk while stirring, then water.  Add salt, pepper and soup mix until slightly thickened.  Remove from fire.  Add vegetables and tuna.  Dump in pie shell and cover with crust.  Make air vent slashes for steam, brush top with egg white.  Bake at 350 degrees for 45 minutes, until crust is golden brown.  Serve hot.