Preheat oven to 375°.
Lightly spoon flour into dry measuring cups; level with a knife. Combine flour and next 4 ingredients (flour through salt), stirring well with a whisk.
Place sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 2 minutes). Add rind, and beat to combine. Add egg and egg white, 1 at a time, beating well after each addition.
Combine buttermilk and ricotta, stirring well with a whisk. Add flour mixture and buttermilk mixture alternately to sugar mixture, beginning and ending with flour mixture. Fold in cranberries. Spoon batter into 12 muffin cups coated with cooking spray. Bake at 375° for 20 minutes or until a wooden pick inserted in center comes out clean. Cool in pan 10 minutes on a wire rack; remove from pan. Cool completely on wire rack.