In a saucepan, blend butter, (melted), and flour.
Slowly stir in milk, salt and pepper.
Break tuna apart and add to the sauce along with its broth.
Add drained potatoes and frozen vegetables.
Transfer to 1-1/2 quart casserole.
Top with pastry.
Bake in a hot oven of 425 degrees for 1/2 hour.
This pie may be chilled then reheated.