On medium heat, heat the milk, cream and coffee in a medium saucepan or pot until hot but do not boil, let cool to warm.
In a medium pot add the egg yolks and sugar whisk to combine, whisk in the flour.
Place the pot over low/medium heat, slowly add the warm milk mixture and continue whisking (don’t stop until very thick).
Transfer the pastry cream into a clean bowl, cover with plastic wrap, make sure the plastic wrap touches the pastry cream, refrigerate for at least 3 hours or even better overnight, before using.
Beat the refrigerated cream before using to bring it make to its creaminess.
Notes
The pastry cream will last up to 5 days in the refrigerator. Be sure to use fresh milk that has a longer expiry date.Never freeze pastry cream because it will never have the same creamy texture once it is thawed.