Prepare the sponge cake.

Grease and line a cake pan with parchment paper.

Bring eggs to room temperature.

Melt butter in the microwave.

Sift cake flour twice.

Preheat oven to 180C (350F).

Whisk eggs lightly in a bowl.

Place bowl over hot water (60C/140F).

Add sugar and whisk continuously.

Whisk until batter is thick enough to draw ribbons.

Sift cake flour into the batter.

Fold gently with a rubber spatula.

Add milk and melted butter, mix roughly.

Pour batter into the cake pan.

Tap the pan to eliminate air pockets.

Bake for about 25 minutes.

Remove cake from pan and cool upside down on a grill.

Scrape off the browned part and slice into two 1cm thick slices.

Trim the outer 1cm rim of each slice.

Prepare the syrup.

Microwave sugar and water in a heatproof container until melted.

Brush syrup on both sides of sponge cake slices.

Place one slice in the cake pan and chill in the freezer.

Chill the other slice in the refrigerator.

Prepare the mousse.

Soften gelatin powder in white wine.

Wash and hull strawberries.

Blend strawberries, sugar, lemon juice, and rum into a puree.

Melt gelatin in the microwave.

Pour gelatin into the strawberry puree and mix.

Whip heavy cream until soft peaks form.

Add strawberry puree and mix.

Pour half of the mousse into the cake pan.

Lay the other sponge cake on top.

Pour the remaining mousse and even out the surface.

Chill in the refrigerator for 2 hours to set.

Warm the sides of the pan with a hot cloth and unmold the cake.

Decorate as desired.