I am not the best with guessing ingredient quantities so after I made a batch of chocolate ganache cupcakes I was left with half a bowl full of ganache. When life gives you leftover ganache, make chocolate truffles.
You could of course make the ganache specially for truffles. Recipe below:
200g chocolate
100ml cream
3 tbsp cocoa
Bring cream almost to a bowl in a saucepan. Take off heat and stir in chocolate until melted. Leave to cool at room temperature until ganache is firm enough to roll. Shape into balls of desired size and roll in cocoa.
100 Days Of Evelyn 
I’m like pavlov’s dog when it comes to chocolate!