Mix the eggs with the sugar.
Heat the mixture to 40-50C, stirring constantly, the sugar melts, and the eggs will incorporate more air during the beating.
Beat the mixture in a mixer for 15-20 minutes at medium speed.
Add the sifted flour, starch potatoes, and almond flour and mix with a spatula from the bottom to the top to obtain a homogeneous consistency.
Put the mixture into the cake pan properly greased and lightly floured.
Bake in a preheated oven at 180°C (356°F) for about 40-50 minutes, never open the oven before 35 minutes.
Do the toothpick test to check cooking, insert it in the center of the cake, and has to come out clean.
After the time necessary to allow it to cool has passed, remove it from the mold.
Let the sponge cake cool completely before slicing.
Blood Orange Cream
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 orange zest and whisk vigorously until it’s completely combined.
When the mixture is blended, add the cornstarch to the mixture, stir well to incorporate it.
Pour the milk and the blood orange juice into the mixture of egg yolks.
Put it on the stove and stir constantly with a whisk.
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.
The orange cream will then be ready to fill the cake.