Beat 6 egg whites (3/4 cups of egg whites) and beat until stiff and set aside. Cream shortening, butter, and sugar until fluffy in a large mixing bowl. In a separate bowl, sift together flour, baking powder, and salt. Now add dry ingredients to the creamy mixture alternately with your milk and water- blend well and beat on medium speed for 3-4 minutes. Once blended, then fold your egg whites into mixture slowly until well mixed. Pour into 2 9 inch cake pans that are greased and floured. Bake 350º for 30-35 minutes. This cake will shrink a little- that is normal. Let cool for 5 minutes, then shake gently to loosen cake but leave in pan until slightly cooled. Then remove from pan and place on plastic wrap. When completely cool, take a large knife with teeth and cut through the cake horizontally to add the lemon filling.
Mix dry ingredients in a large sauce pan and add egg yolks. Add a little water and lemon juice first until you have a paste and then gradually add the rest until well blended. Mix in lemon rind. Cook over medium heat until it comes to a boil and boil until thick (2-3 minutes, stirring continuously). Reduce heat and simmer for a couple of minutes. Set aside from heat to cool and stir periodically. Once slightly cooled, take the top half of your cake and flip it over onto a cake plate so your cut portion is exposed and the rounded top is on the cake plate. Spread 1/3 of the filling on top with a spoon and leave about 1/4 inch from the edge. Put the bottom half of the sliced cake on top of it with the flat side exposed. Add another 1/3 of filling on top of this, leaving it a 1/4 inch from the edge and spread evenly. Take the bottom half of the other cake and lay on top keeping the cut side exposed. Add the last 1/3 of filling on top of that and spread, leaving it a 1/4 inch from the edge. Finish off with the top layer of cake keeping the rounded part exposed. Refrigerate to cool for 1 hour. Cover with whipped cream icing.
Whipped Cream Frosting-The Original:
3 Tbs flour
1/3 cup of milk
1 1/2 sticks of butter
3/4 cup of sugar
1 1/2 tsp vanilla
Mix flour and milk a little at a time to avoid lumps. Cook over medium-low heat until thick like a paste. Stir continuously while in saucepan over heat. Set aside and leave it cool completely, stirring periodically. Add butter, sugar, and vanilla into a separate bowl, beat with electric beater until creamy and then add the cooled flour and milk mixture. Beat with mixer 3-5 minutes until creamy and fluffy. Spread on lemon torte cake.