Preheat oven to 350°.
Coat an 8-inch round cake pan with cooking spray.
Line bottom of the pan with parchment paper.
Coat paper with cooking spray.
Set aside.
Lightly spoon flour into dry measuring cups; level with a knife.
Combine flour and all dry ingredients (except the lemon zest) in a large bowl, stirring well with a whisk.
Make a well in center of mixture.
Combine buttermilk, oil, eggs, lemon juice and lemon rind, stirring well with a whisk.
Add buttermilk mixture to flour mixture, stirring until moist.
Pour batter into prepared pan.
Bake at 350° for 40 minutes or until wooden pick inserted in center comes out clean.
Cool in the pan 10 minutes on a wire rack; remove from pan.
Cool completely on wire rack.