HEAT oven to 400ºF.
COVER bottom of 9-inch round pan with parchment; spray with cooking spray. Mix 1/4 cup butter and 1/2 cup sugar with mixer until blended; spread onto bottom of prepared pan. Arrange mangos in circular pattern over butter mixture in pan.
BEAT remaining butter and sugar in large bowl with mixer until light and fluffy. Blend in egg and sour cream. Add combined flour, ginger and baking soda; beat on low speed just until blended. Carefully spread over mangos.
BAKE 30 min. or until toothpick inserted in center comes out clean. Cool cake in pan 5 min. Run knife around edge of pan to loosen cake; invert onto plate. Remove pan and parchment. Serve cake warm topped with COOL WHIP.