How to Make It
Combine first 4 ingredients in a mixing bowl. Make a well in center of flour mixture; add oil, egg yolks, and orange juice. Beat at medium-high speed with an electric mixer 3 to 4 minutes or until smooth. Stir in rind.
Beat egg whites and cream of tartar at medium-high speed with an electric mixer until stiff peaks form. Gently fold into flour mixture. Spoon batter evenly into 3 greased and floured 9-inch round cakepans.
Bake at 350° for 18 to 20 minutes or until a wooden pick inserted in center comes out clean. Cool in pans on wire rack 10 minutes; remove from pans, and cool completely on racks.
Spread Orange Icebox Pie Filling evenly between layers and on top of cake. Cover cake, and chill at least 4 hours.
Spread Orange Buttercream Frosting evenly around sides. (Cake may be frozen up to 1 month completely assembled.)
Note: Cake batter may be baked in 3 (10-inch) round cakepans or 2 (13- x 9-inch) baking pans for 15 minutes or until a wooden pick inserted in center comes out clean.