In a bowl, put the gelatin leaves and cover them in cold water to soften them. Leave them about 5 minutes then drain and dry out.
Bring the milk with the sugar and the ground almonds to a boil then mix in the gelatin. Strain through a fine strainer to remove the bits of almonds then put in the frdge.
Whip the cold double cream with an electric whisk and mix it into the cold almond milk. Then pour this mixture into pastry rings or into individual silicone molds and put in the fridge for 2 hours or in the freezer for 30 minutes.
Peel the pineapple and cut in 4 lengthwise, then into fine slices (if you have one, use a pineapple peeler to get even slices). Slice the vanilla pod in 2 and scrape the inside.
Marinate the pineapple in the rhum and vanilla seeds.
Preheat the oven to 200 °C.
In a bowl, mix well the flour, the butter, the salt, the sugar and the egg yolks. Then place this dough between 2 sheets of greaseproof paper and roll it until is 5mm thick. Put it in the oven for 15 to 20 minutes.
When it's done, cut the shortbread with the same pastry rings as the blancmange to make individual shortbreads.
Place the shortbead on a plate. Put the blancmange on top, then pineapple slices. To finish, drizzle everything with the marinade.
«Keep the pineapple leaves to decorate this dessert. You can serve it with a fruit coulis.»