Have frosting ready and at the temperature you like to frost with.
Preheat oven to 320°F.
Prepare cake pans: Coat bottoms of 3 (8-inch) round cake pans with cooking spray. Do not coat sides of the cake pans. Place wax paper on the bottom of the three cake pans and then spray the top of the wax paper with the cooking spray. Dust the wax paper bottom of all three pans with 1 table spoon of flour.
Lightly spoon 2 cups cake flour into dry measuring cups, and level with a knife. Combine 2 cups cake flour, 1 cup sugar, baking powder, and ½ teaspoon salt in a large bowl, stirring with a whisk until well combined.
Combine oil, 1/3 cups juice, 3 tablespoons water, 1 teaspoon rind, lemon extract, and egg yokes in a medium bowl, stirring with a whisk. Add oil mixture to flour mixture; beat with mixer at medium speed until smooth.
Place egg whites in a large bowl; beat with mixer at high speed until foamy. Add cream of tartar; beat until soft peaks form. Gradually add remaining 1/4 cup sugar, 1 tablespoon at a time, beating until stiff peaks form. Gently stir one-fourth of the egg white mixture into flour mixture; gently fold in remaining egg white mixture.
Divide cake batter equally among prepared pans, spreading evenly. Break air pockets by cutting through batter with a knife. Bake at 325 degrees for 20 minuets or until cake springs back when lightly touched. Cool in pans for 10 minuets on a wire rack; remove from pans. Remove wax paper from cake layers. Cool completely on wire racks.
To assemble cake, place 1 cake layer on a plate; spread half of the filling over the cake layer. Top with second cake layer, remaining half of the filling, and third layer. Spread frosting over top and sides of cake. Garnish with mint, blueberries, and lemon wedges, if desired. Store cake loosely in refrigerator for up to three days. Slice into cake wedges.