Pour the milk into a medium-sized saucepan. Split the vanilla bean lengthwise and scrape out the seeds. Add the seeds and the empty pod to the milk. Heat the vanilla-infused milk until almost boiling, then remove from heat and discard the vanilla pod.
In a medium-sized bowl, whisk together the egg yolks and starch until well combined. Add the sugar and mix again.
Slowly pour the hot milk into the egg mixture while stirring continuously. Transfer the mixture back into the saucepan and cook over medium heat, stirring constantly to prevent the mixture from burning or forming lumps. Once the vanilla cream thickens, continue stirring for another half minute.
Remove from heat and transfer the cream to a very shallow bowl. Cover the surface of the cream with plastic wrap to prevent a skin from forming. Let the vanilla cream cool completely at room temperature (not in the fridge!).
Cream the mascarpone until smooth. Also, smooth out the cooled vanilla cream. Gradually fold the mascarpone into the vanilla cream.
Notes
You can enjoy this Vanilla Mascarpone Cream as it is or use it as a delightful filling for cakes and pastries!