Blend the two sugars and the water in a saucepan. Give it a light boil on medium heat flame. Also, keep baking molds ready in front of you. Dip the thermometer into the boiling sugar and take out the pan from the heat when the temperature reaches 160 ° C. Quickly drizzle up a layer of caramel on it, about 2 cm thick. Allow it to get cool.

In the lengthwise direction, chop the half vanilla pod. Poke the inner side with a sharp knife to take out the tiny black seeds. Boil its seeds and milk with the vanilla in a saucepan. Quickly blend the whole eggs, the sugar, and yolks by hand whisking in a bowl. Gently stream the warm vanilla milk, and then combine by whisking with hand. Get the oven ready by preheating it to 160 ° C.

Very gently, take out the half vanilla pod. In a very delicate manner, use a small ladle to stream egg cream and fill up the caramelized molds, keep in a plate with high edges and afterward stream little lukewarm water in it to make a double boiler almost near the height of the molds. Keep baking it for 15 to 20 minutes; cooking time would depend on the size of the molds. To avoid some mishaps, carefully pay attention to the consistency of the cream. The cream must get a little clotted yet should be trembling, and it should not solidify too much. Take out the mussels from the oven, also double boiler, then store them about 2 hours in the refrigerator. Serve the dish chilled!