Preheat oven to 375°F.
Prepare two 10″ pans as described in my cake-making 101 post.
Whip together the oil, egg yolks, and lemon zest until just combined. Stir in the water, lemon juice, and vanilla extract until combined.
In a separate bowl, sift together the cake flour, 3/4 cup sugar, baking powder, and salt. Stir this into the egg yolk mixture. Whip at a high speed for 1 minute and set aside.
In a separate bowl, whip together the egg whites to foam. Gradually add the remaining 1 1/4 cup sugar and continue whipping until soft peaks form.
Carefully fold the meringue into the reserved batter.
Pour batter into prepared pans. Fill pans about 2/3 full
Bake at 375° F for approximately 25 minutes. When a cake is done it should spring back when pressed lightly in the center or when a toothpick comes out clean. Do not overcook.
Cool cakes before frosting with my fluffy lemon buttercream frosting recipe.