For the chocolate sponge cake, here’s a quick overview since basic cake making is familiar to most. Separate the egg whites and beat them with sugar and 1 teaspoon lemon juice until stiff peaks form. In another bowl, whisk the yolks with milk and oil, then sift in the flour and gently fold together with the egg whites. Finally, add vanilla and melted chocolate, mix until smooth, and bake at 350°F for 15 minutes.

Prepare the molds and food coloring. Boil 6 1/3 cups water (about 1.5 liters), then mix agar powder with superfine sugar. When the water boils, gradually add the agar-sugar mixture, stirring until dissolved. Add food coloring and pour into shell-shaped silicone molds. Once the cake has cooled, cut out a crescent shape, spread a little whipping cream inside, and crumble the cut cake to create a sandy texture.

Press some of the cake through a sieve to make coral shapes, then mix in a little blue food coloring and whipping cream to get the desired color.

Arrange the cake pieces to form natural-looking rocky outcrops on the cake. Remove the jelly shell shapes from the molds and place them on the cake and around the base to resemble the sea floor. Sprinkle a little toasted shredded coconut on top to look like snow.

Finally, pour the remaining jelly mixture around the cake to create a clear blue sea. Decorate the rest of the cake to make the island scene more lively, adding colorful chocolate rocks around the coconut tree and throughout the island for a wild, natural look.