In a pastry board put the cold butter cut into small pieces with the sifted flours, sugar, and the baking powder, work everything with your hands until it becomes grainy.

Form a hole in the center of the sand and add the egg yolks one at a time, and knead until everything is combined.

If the dough is too hard and dry, add a little cold water little by little, until you get a smooth and homogeneous dough.

Shape the dough into a ball, wrap it in cling film, and let it rest in the refrigerator for at least 60 minutes.

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 and whisk vigorously until completely combined.

When the mixture is blended, add the corn starch sieved in, stir well to incorporate it.

Pour the milk into the mixture of egg yolks, sugar, and corn 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 is complete at just 67°C (152.6°F).

If it is cooked too much, the cream will have a strong smell of egg.

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 pastry cream would be ready for use; otherwise cover with plastic wrap in contact with the surface of the cream, let it finish cooling at room temperature, and then refrigerate.

Roll out the dough until it is about 4 mm (1/8 inches) thick and cut out an even number of discs with a diameter of about 8 cm (3 inches).

Place 1 1/2 tablespoons of custard in the center of each disc .

Cover with another disc, sealing everything around with your fingers and trimming the edges with a pastry wheel

Bake the Genovesi in a preheated oven at 200°C (392°F) until golden brown (about 10 minutes).

Once taken out of the oven, sprinkle the pastries with plenty of icing sugar and serve when still hot enough.