Leave the butter out of the fridge until it has a pasty texture.
Chop the black truffle and mix it with the butter.
Line an airtight container with cling film, put butter inside and leave it in the fridge for about 5 days.
When we want to enjoy it, we take it out of the fridge a while before. And we can enjoy it with bread or in a variety of recipes.
Bon appetit!