Delicious Coffee Cake

Ingredients

• Coffee Sponge Cake:
• 6 eggs
• 1/2 cup fine sugar
• 1/2 cup instant coffee powder
• 3/4 cup flour
• 1 tablespoon vinegar
• 2 tablespoons oil
• 1 teaspoon baking powder
• a pinch of salt
• Light Sponge Cake:
• 3 eggs
• 1/3 cup fine sugar
• 1/2 cup flour
• 1 tablespoon oil
• Custard Cream:
• 500 ml milk
• 2 tablespoons sugar
• 3 teaspoons vanilla sugar
• heaping tablespoon wheat flour
• heaping tablespoon cornstarch
• 200 g butter