Add the milk and vanilla extract to a pot and heat. (Just until it starts to simmer).
Add the eggs, sugar, and cornstarch in that order to a bowl and mix.
Add the milk a little at a time while mixing.
Pour the mixture into the sauce pan through a sieve and raise the heat to high while mixing. Once it comes to a boil, stop the heat, add the butter and rum, and mix.
When making custard cream this is it. Put the pot in ice water to cool quickly.
Add the minced chocolate to Step 4 and mix evenly.
Put the pot in ice water to cool quickly.
Story Behind this Recipe
Just add chocolate to custard cream.
After cooling... lay plastic wrap across the pot, put the cream on it, then use the wrap to pull it out. Cooling all at once helps to prevent bacteria from forming. It'll be spongy when you go to use it, so whisk it before using.