Bloom the gelatin by sprinkling it over the cold water in a small bowl and letting it sit for 5 to 10 minutes.

In a medium saucepan, combine the whole milk with half of the granulated sugar (1/4 cup) and the vanilla bean. Heat over medium heat until steaming but not boiling.

In a separate bowl, whisk the egg yolks with the remaining 1/4 cup of sugar until pale. Gradually whisk in half of the hot milk into the yolks, then return to the saucepan.

Cook the custard over medium-low heat, stirring constantly until it thickens slightly, about 4 to 5 minutes.

Remove the pot from heat and strain the custard. Stir in the bloomed gelatin until dissolved.

Let the custard mixture cool to room temperature.

Whip the heavy cream to soft peaks and gently fold it into the cooled custard in two additions.

Transfer the mixture into a mold and refrigerate for at least 4 hours until set.