Preheat the oven to 350 degrees F.
Spray oil on a pan 8" x 11" and set aside.
Sift the flour, salt, cornstarch, and baking powder together into a bowl.
In another bowl, cream the eggs, sugar, vanilla, and oil.
Add the lemon zest and mix.
Add some of the flour mixture to the egg mixture.
Then add some milk.
Do this little by little, alternating between the dry and wet ingredients.
Continue until the batter is smooth, and there are no more ingredients.
Pour into the prepared pan and bake for 20-25 minutes.
The cake is ready when the toothpick comes out clean from the center of the cake.
Remove the cake from the oven and let cool.
Once the cake is completely cool, prepare the frosting.