Luscious Lemon Cake

Hello all-
I know I've been bad and haven't contributed any recipes yet, so here goes. I hope you enjoy it!

1 package white cake mix
1 cup water
1/4 cup sugar
2 eggs beaten
2 tbsp. cornstarch
2 tbsp. sugar
Zest of 1 lemon
1 tbsp. butter
3 tbsp. fresh lemon juice
1 pint sweetened whipping cream (I just used cool whip)
1/4 cup white chocolate shavings

Grease and flour 2 9inch cake pans. Set aside. Preheat oven and make cake according to package directions on cake mix. When cake is done, put on cake racks and cool completely. While cake is cooling prepare lemon filling.

Put water, 1/4 cup sugar, and beaten eggs in a small saucepan. Mix cornstarch and 2 tbsp. sugar together in a small bowl. Slowly add to mixture in pan. Cook on medium heat, stirring constantly until thickened. When thickened add lemon zest, butter, and lemon juice. Stir until butter is melted and mixture is well mixed and smooth. Remove from heat and let cool. Cover with plastic wrap while cooling. When cake is cool, cut each layer in half to make 4 slices. Place a layer on a serving plate and spread with 1/2 of cooled lemon filling. Add second layer of cake and spread with whipped cream. Add third layer of cake and spread with the remaining half of the lemon filling. Top with fourth layer of cake. Frost sides and top of cake with whipped cream. Garnish with white chocolate shavings. Refrigerate until ready to serve. Serves 12 to 16.