Preheat the oven to 340°F (170°C).

In a bowl, whisk together the eggs, sugar, and vanilla sugar until you achieve a light foam. Add the heavy whipping cream and oil, and whisk well. Then, add the flour, baking powder, and white chocolate, and stir until you obtain a smooth batter. Transfer the batter to a bread loaf pan and drizzle a small amount of caramel spread over it. Use a skewer to create a marble-like effect. Bake for approximately 40 minutes.

Remove the cake from the oven and let it cool slightly. Then, take it out of the pan and drizzle caramel spread over the top to cover the cake.