Preheat oven to 350°.
Coat an 8 x 4-inch loaf pan with cooking spray; dust with 2 teaspoons flour.
Lightly spoon 1 cup flour into a dry measuring cup; level with a knife. Combine 1 cup flour and baking powder, stirring with a whisk; set aside.
Place sugar and butter in a large bowl; beat with a mixer at high speed until fluffy (about 2 minutes). Add egg whites and egg, beating well after each addition. Beat in rind and extract. Add flour mixture and 1/4 cup yogurt alternately to sugar mixture, beginning and ending with flour mixture; mix well after each addition. Spoon batter into prepared pan. Bake at 350° for 45 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on wire rack; remove from pan. Cool completely on wire rack.
To prepare topping, combine berries, tossing well. Cut cake into 8 slices. Top each cake slice with 1/4 cup berry mixture and 2 tablespoons yogurt.