Put the milk with the scraped vanilla pod in a small saucepan, and bring it to a boil.
Remove the pan from the stove and filter the milk.
Separately, in a bowl pour the egg yolks, the vanilla caviar, sugar, and the grated zest.
Whisk vigorously until completely combined.
When the mixture is blended, add the cornstarch sieved in, stir well to incorporate it.
Pour the milk into the mixture of egg yolks, sugar, and rice starch.
Put on the stove and stir constantly with a whisk (the egg begins to coagulate at 52 °C (125.6°F) temperature; the cooking should stop when it reaches just 67°C (152.6°F).
Remove the cream from the stove as soon as it starts to thicken.
Cool it quickly by pouring it into a cold pan and continue to stir with a whisk bringing it to a temperature below 50°C (122°F), this allows it to maintain the consistency of the cream intact.
Cover with plastic wrap in contact with the surface of the cream, let it finish cooling at room temperature.