In a medium sized bowl, combine all-purpose flour and baking soda. Set aside.

In a large bowl, beat together butter and sugar until light and fluffy. Next beat in egg. Add sour cream and vanilla and continue to beat until well blended. Stir in flour, followed by dried mangoes and pistachios.

Drop tablespoonfuls of dough 2 inches apart onto baking sheet. Flatten the top slightly. Bake in 350&#176F (180&#176C) oven for 15 minutes. Remove and cool on wire rack.