In a medium mixing bowl stir together flour and the 1/4 teaspoon salt. Using a pastry blender cut in shortening until pieces are pea-size.
Sprinkle 1 tablespoon of the water over part of the mixture; gently toss with a fork. Push moistened dough to the side of the bowl. Repeat, using 1 tablespoon of the water at a time, until all the dough is moistened. Form dough into a ball.
On a lightly floured surface roll dough into a 13-inch circle. Ease pastry into an ungreased 11-inch tart pan with a removable bottom. Press pastry into pan; trim edges. Prick bottom and sides of pastry. Line with a double thickness of foil. Bake in a 450 degree F oven for 8 minutes. Remove foil. Bake 5 to 6 minutes more or until lightly browned. Cool completely in pan on a wire rack.
For filling, in a heavy, medium saucepan stir together sugar, cornstarch, and the 1/4 teaspoon salt. Place sliced mango in blender container or food processor bowl. Cover; blend or process until smooth (should have 1-1/2 cups). Stir mango and yogurt or sour cream into sugar mixture. Cook and stir over medium heat until thickened and bubbly. Cook and stir 2 minutes more. Remove from heat.
Slightly beat egg yolks, Gradually stir about 1 cup of the hot filling into egg yolks. Pour egg yolk mixture into hot filling in saucepan. Bring to gentle boil. Cook and stir for 2 minutes more. Remove from heat. Stir in lime juice.
Pour warm filling into pastry shell. Cool for 1 hour on wire rack. Chill in refrigerator for at least 4 hours before serving; cover for longer storage. If desired, garnish with fresh fruit. Makes 8 servings.
You can use fresh mangos or refrigerated mango slices in a jar (found in the supermarket produce section) in this pie.