Mix Dry Ingredients: In a saucepan, combine the sugar and cornstarch. Mix well.

Add Milk: Gradually add the milk to the mixture, stirring constantly to avoid lumps.

Cook the Mixture: Place the saucepan over medium heat and cook, stirring constantly, until the mixture thickens and starts to boil.

Add Lemon Juice: Once thickened, remove from heat and slowly add the fresh lemon juice while stirring.

Incorporate Egg: Beat the egg in a separate bowl and gradually add it to the lemon mixture, stirring continuously to combine.

Add Food Coloring: Add a few drops of yellow food coloring to achieve a vibrant lemon color.

Cool Down: Pour the lemon cream into a bowl, cover it with plastic wrap to prevent a skin from forming, and let it cool to room temperature.

Preheat Oven: Preheat your oven to 180°C (350°F).

Beat Eggs and Sugar: In a large bowl, beat the eggs with the sugar, vanilla sugar, and a pinch of salt until the mixture is light and fluffy.

Add Wet Ingredients: Gradually add the vegetable oil and milk, mixing until well combined.

Incorporate Dry Ingredients: Sift together the flour and baking powder, then gradually add them to the wet mixture, folding gently to avoid deflating the batter.

Bake the Cake: Pour the batter into the prepared baking pan (28 cm x 18.5 cm) and bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Cool the Cake: Once baked, let the cake cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.

Layer the Cake: Once the cake is completely cooled, cut it into two equal layers.

Add Lemon Cream: Spread the lemon cream evenly over the bottom layer of the cake.

Top Layer: Place the top layer of the cake over the lemon cream.

Chill: Refrigerate the assembled cake for at least 2 hours to allow the cream to set and flavors to meld.