Preheat oven to 350 F (180C). 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. Cook 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. Refrigerate until ready to serve.