It's common to eat Christmas cakes on Christmas Eve in Japan.
Typical Japanese Christmas cakes are round sponge cakes with whipped cream and fruit toppings. To bake a fluffy sponge cake, make sure to whisk eggs very well.
For sponge cake:
• 3/4 cup all purpose flour
• 2/3 cup sugar
• 1 Tbsp milk
• 3 eggs
• 1 1/2 Tbsp butter
• 1 1/2 cups heavy cream
• 4 Tbsps sugar
• Various fruits (strawberries, peaches, cherries, and so on)
Whisk eggs in a bowl. Place the bowl over warm water in another large bowl and whisk further. Add sugar little by little. When the egg mixture becomes light yellow, sift flour and add to the bowl. Mix the flour lightly in the egg mixture. Mix butter in warm milk. Add mixture of melted butter and milk in the batter and stir gently. Preheat the oven in 350-degree F. Place baking wax papers inside of a round cake pan (18cm). Pour the batter in the pan and bake in the preheated oven for 25-35 minutes. Remove the cake from the pan and cool it on a rack. Cut the cake in half horizontally. Mix heavy cream and sugar in a bowl. Whip the cream well. Take the half of the whipped cream and mix with chopped fruits. Place the cream on top of a round cake slice. Place another cake slice on top of the cream. Spread the rest of the whipped cream on top and around the cake. Decorate the cake with colorful fruits and Christmas decorations.