In the container in which you'll be boiling the cream, put the yolks and sugar, beat until homogeneous.
Add the cold milk, starch and vanilla. Stir until fully dissolved in the milk to a smooth mixture.
Put the container on low heat and boil until the cream thickens, while stirring nonstop.
Cover the container with plastic wrap and leave the cream to cool completely.
Beat the liquid cream until fluffy, add the cream mixture to it in lots, while stirring nonstop with a mixer.
What you get is an incredibly fluffy and airy cream for cakes and not just... the favorite cream for everyone at home!