Heat the milk in a saucepan. If using a vanilla bean, vertically slice the vanilla bean with a small knife and extract the inner seeds, then add them to the milk.

In a separate bowl, add egg yolks, sugar, flour, and cornstarch. Whisk well with a soft whisk to blend all the ingredients.

As soon as the milk reaches a simmer, pour it into the egg mixture a little at a time, continuing to whisk.

Return the mixture to the saucepan and cook over medium heat, stirring continuously, until it thickens.

At this point, turn off the heat, add a pinch of salt and vanilla extract (if not using a vanilla bean), and mix well. The pastry cream is ready.

Pour the mixture into a bowl and cover it directly with plastic wrap. This will prevent a hard film from forming on the surface of the cream. Allow to cool to room temperature, then refrigerate for 5–6 hours.

Once the pastry cream has cooled, add heavy cream and icing sugar to a large bowl and whip until stiff peaks form. Mix the cooled pastry cream with a soft spatula until it regains a thick consistency.

Gently fold into the whipped cream, and your homemade diplomat cream is now complete and ready to use in your favorite Italian desserts.