Olive Garden's Lemon Cream Cake

1 3/4 cups cake flour
1 tablespoon baking powder
1 teaspoon salt
1/2 cup white sugar
1/2 cup vegetable oil
6 egg yolks
3/4 cup water
1 tablespoon lemon zest
6 egg whites
1/2 teaspoon cream of tartar
3/4 cup white sugar
1 cup heavy whipping cream
2 1/2 cups lemon pie filling
8 slices lemon

Preheat oven to 350 degrees F (175 degrees C).

In a large bowl, combine flour, baking powder, salt, and 1/2 cup sugar. Add oil, egg yolks, water and lemon rind. Beat with an electric mixer until smooth.

In a small bowl, beat egg whites and cream of tartar until peaks form. Gradually add 3/4 cup sugar, and beat until very stiff and shiny peaks form. Fold 1/3 of the whites into the batter, then quickly fold in remaining whites until no streaks remain. Turn batter into ungreased 10 inch tube pan.

Bake at 350 degrees F (175 degrees C) for 60 minutes or until a toothpick inserted in the center comes out clean. Invert cake and cool completely in pan. When cool, loosen edges and shake pan to remove cake.

FILLING
Beat cream to stiff peaks. Fold in lemon filling. Chill until stiff.

ASSEMBLY
Slice cake horizontally into 3 equal layers. Fill layers with 1/3 cup of filling. Spread remaining filling on top layer. Decorate with lemon slices.