Lightly spoon flour into dry measuring cups, and level with a knife. Combine flour and next 5 ingredients (flour through cardamom) in a medium bowl; make a well in center of mixture. Stir in mango. Combine buttermilk, butter, vanilla, and egg; add to flour mixture, stirring just until moist (batter will be stiff).
Spoon batter into 12 muffin cups coated with cooking spray; sprinkle evenly with 2 tablespoons sugar. Bake at 400° for 23 minutes or until the muffins spring back when touched lightly in center. Remove muffins from pans, and cool on a wire rack.