Preheat oven to 350°.
Coat 2 (8-inch) round cake pans with cooking spray; line bottoms of pans with wax paper.
Coat wax paper with cooking spray.
Dust pans with 2 tablespoons flour, and set aside.
Lightly spoon 2 cups flour into dry measuring cups, and level with a knife.
Combine 2 cups flour, baking powder, baking soda, and salt, stirring with a whisk.
Place sugar and 1/2 cup butter in a large bowl; beat with a hand-held blender/mixer at medium speed until well blended.
Add eggs, one at a time, beating well after each addition.
Add flour mixture and buttermilk alternately to sugar mixture, beginning and ending with the flour mixture.
Beat in 2 tablespoons lemon zest and 2 tablespoons lemon juice.
Pour batter into prepared pans.
Bake for 20 minutes or until a wooden pick inserted in center comes out clean. Do not overbake.
Cool in pans 10 minutes on a wire rack; remove from pans.
Cool completely on wire rack; remove wax paper from cake layers.
With a hand-held electric blender, combine powdered sugar and the remaining ingredients in a large bowl.
Place 1 cake layer on a plate; spread half of icing on top of cake.
Top with remaining cake layer.
Spread remaining half of icing over top of cake.
Garnish with lemon wedges or strips, if desired.
I also added a sprig of fresh mint from my garden.
Store cake loosely covered in the refrigerator.
