Pastry bags filled with custard and ricotta

INGREDIENTS
For the cannoncini dough:

500 g of 00 flour for cakes;
50 g of lard or butter;
1 whole egg;
50 g of granulated sugar;
Half a cube of brewer’s yeast;
250 ml of milk;
8 g of salt;
Peanut oil for frying the Cartocci to taste
Ricotta cream:

300 g of well-drained ricotta;
180 g of sugar
Custard:

500 ml of milk;
4 egg yolks;
150 g of granulated sugar;
The grated rind of a lemon;
60 g of corn starch;
Granulated sugar