Preheat the oven to 180 °C (356 °F) with top and bottom heat. Grease and line your baking pan (18 x 28 cm).

In a mixing bowl, beat the eggs with sugar and a pinch of salt until light, fluffy, and doubled in volume. This aeration is key to a soft sponge.

In a separate bowl, combine flour with baking powder, then gently fold it into the egg mixture. Take care not to deflate the batter.

Pour the batter into the prepared baking pan, spreading it evenly. Bake for 12–15 minutes until golden and springy to the touch. Allow the sponge to cool completely before adding the pudding layer.

For the pudding, heat the milk in a saucepan. Meanwhile, whisk together eggs, cornstarch, sugar, vanilla sugar, lemon peel, and both lemon and orange juice until smooth.

Slowly pour this mixture into the hot milk while whisking constantly. Cook over medium heat until thickened and creamy. Remove from the heat and let cool slightly.

Once the pudding is warm but not hot, beat in the cream cheese until fully incorporated, creating a smooth, tangy cream.

Spread the lemon pudding mixture evenly over the cooled sponge cake.

Refrigerate the cake for at least 3 hours, preferably overnight. This step allows the pudding to set and the sponge to absorb moisture, making it even more tender.

Slice into squares or rectangles and serve chilled. Garnish with a dusting of powdered sugar, lemon zest, or fresh berries if desired.