Prepare one 9-inch pastry shell, crimping edges high.
Prick pastry lightly.
Bake at 450Â° till lightly browned, about 7 minutes.
Remove from oven; reduce oven temperature to 325Â°.In medium saucepan gradually blend 1 1/2 cups milk into one 3-ounce envelope cream of potato soup mix, 1 teaspoon dry mustard, and dash pepper.
Cook and stir till thickened and bubbly.
Press mixture through sieve; discard any remaining potato chunks.
Stir in 1/2 cup light cream.
Combine 3 slightly beaten eggs; 4 ounces process Swiss cheese, shredded (1 cup); and 2 tablespoons finely chopped green onion with tops.
Blend soup mixture into cheese mixture.
Set aside while preparing salmon layer.Drain one 7 3/4-ounce can salmon.
Remove skin and any large bones.
Combine salmon and 3 tablespoons soft bread crumbs.
Sprinkle evenly in partially baked pastry shell.
Carefully pour in soup mixture.
Bake at 325Â° till knife inserted off-center comes out clean, 50 to 60 minutes.
Let stand 10 minutes.
Cut into tiny wedges; serve warm.