To make custard, place gelatine sheets in a large bowl with very cold water and soak for 10 minutes. Whisk egg yolks with sugar with an electric mixer in a medium-sized bowl until the mixture whitens.

In a heavy-bottomed medium saucepan, warm milk with the split and scraped vanilla bean over medium heat. When it almost boils, remove the empty vanilla pod, and pour the hot milk over the egg yolk mixture, stirring vigorously. Pour the milk mixture with tempered yolks back into the saucepan, scraping the bottom of the bowl for the remaining vanilla seeds with a spatula.

Heat the preparation over low heat, stirring constantly, until the custard reaches 179°F (82°C). Don't exceed the maximum temperature of 183°F (84°C); otherwise, the eggs will curdle, and the cream will resemble scrambled eggs. 

Off the heat, add the well-drained gelatin and mix well. Pour the custard into a large bowl (or shallow dish) and cover it with plastic wrap in contact. The film must touch the cream's surface to prevent skin formation. Let the cream cool on the counter (it takes some time), in the refrigerator or freezer to speed up the chilling process. Check the custard's temperature regularly if placed in the fridge or freezer! The cream must be cooled down to 73-86°F (23-30°C).

To make whipped cream, place the bowl of a stand mixer and the whisk attachment in the freezer for 10 minutes. Pour cold heavy cream into the bowl and whip cream until soft peaks.

Gently fold the whipped cream (without whisking) into the cooled custard in 3 or 4 times. Pour the cream mixture into the molds to make the Bavarois dessert or fill a Charlotte cake. The setting time varies from 2 to 4 hours, depending on the mold size. You can also transfer the cream to a piping bag to fill cupcakes or choux pastry.