To make the charlotte sponge cake:

Preheat the oven to 350°F (180°C).
Beat the egg whites with the sugar until stiff peaks form. Gradually add the egg yolks at a lower speed, then gently fold in the flour at low speed or by hand with a spatula to avoid deflating the mixture.
Pour the batter into a silicone mold, filling it about three-quarters full. Bake for about 25 minutes or until a knife inserted comes out clean. Let cool, then carefully remove from the mold.

To make the vanilla syrup:
Dissolve the sugar in the hot water, let it cool, then add the vanilla extract.
To make the three milk cream:
Soak the gelatin sheets in cold water for about 10 minutes, then microwave to fully dissolve. Whip the heavy cream, then gradually add the sweetened condensed milk and evaporated milk. Add the rum and raspberry puree or jam, and finally fold in the dissolved gelatin. Chill in the refrigerator until set.

To assemble the dessert:

Once the sponge cake is ready, use a bread knife to cut a lid off the top, then carefully hollow out the inside without breaking the sides. Lightly brush the inside and the removed cake pieces with the vanilla syrup. Fill the hollowed cake by alternating layers of the three milk cream, the syrup-soaked cake pieces, and raspberries. Close with the reserved lid.
Decorate with whipped cream, small meringues, or just fruit. Refrigerate for at least 2 hours before serving. Enjoy!