°3 c flour
°3 tsp baking powder
°1 t of salt
°1/3 c butter
°1 1/4 c white sugar
°4 egg
°1 t vanilla extract
°1 c milk
°1 t grated lemon zest

*Methods :

Preheat oven 360 degrees F - 170 degrees C - greased & flour 2 7-inch round pans mixing flour baking powder also salt set apart
in  bowl, cream butter & sugar to light also fluffy about 6 min, stirring in the eggs one at a time, & stirring in vanilla, beat the flour blend alternately with milk to mixing until incorporated
  pour batter to prepared pans bake in preheated oven for 35 min the filling - in a medium saucepan combine 1 tbsp lemon zest 1/3 cup lemon juice and 1 tbsp cornstarch until smooth combine 5 tbsp butter and 3/ 4 cup sugar and bring the mixture to a boil over medium heat boil for one minute stirring constantly in a small bowl, with a whisk, beat the egg yolks until smooth, stir in a small amount of the lemon mixture hot, pour egg mixture into saucepan, beating hot lemon mixture quickly, reduce heat to low, stirring constantly 5 minutes or until thickened - do not boil - pour mixture into a medium bowl squeeze a plastic wrap over surface to prevent skin from forming on cooling cool to room temperature refrigerate 2 hours
  to make the frosting - in a large bowl, beat the icing sugar 1/3 cup butter 3 tbsp lemon juice and 1 tsp lemon zest until smooth, stir in milk and increase the speed and continue beating until light and fluffy
  to assemble - with a long serrated knife, halve each cake layer horizontally making 5 layers place 1 layer cut side up on a serving platter spread with half the lemon filling with another layer and spread with 1/3 cup frosting add third layer and spread with remaining half of the lemon filling press over last layer of cake and frost top and sides of cake with remaining frosting refrigerate cake until ready to serve . 

Enjoy !