Cake: Grease two 9 inch (23 cm) round cake pans and line bottoms with waxed paper.
Break eggs into a large bowl; place over hot tap water for 5 minutes. Add vanilla.
With electric mixer, beat eggs and vanilla on high speed until foamy.
Add sugar gradually and beat until eggs are very light, about 3 minutes.
In another bowl, combine flour and baking powder; stir into egg mixture in three additions. Divide batter between pans.
Bake 20 to 25 minutes, or until cake springs back when touched in center. Cool on cake racks 5 minutes. Turn out of pans, peel off paper and cool completely.
Filling: In a medium saucepan, combine sugar and cornstarch.
Stir in water, cranberries and apples. Bring to a boil over medium heat, stirring. Cook until apples are tender and mixture is thick, 3 to 4 minutes.
Remove from heat and cool.
Slice each cake in 2 to make a total of 4 layers. Place one layer on a serving plate; top with 1/2 cup (125 mL) filling.
Repeat with 2 more layers, placing the last layer on top of cake crust-side up. Spread remaining filling on top. Whip cream with sugar. Frost sides of cake with cream, and pipe a border on top.