Ganache is the combination of chocolate and heavy cream. It can be used as filling, glazing, coating or as a base for making truffles. Depending on the use, the ratio of chocolate to cream is varied to obtain the desired consistency.
For filling and truffles, the usual ratio is 2:1 (chocolate:cream). For glazing, 1:1.
After about 30 minutes in the fridge, it can be whipped and spread to cover a cake. It can also be piped to make beautiful swirls on top of cupcakes.
If left in the fridge for too long, it gets too thick and hard to spread.
No matter the ratio you choose, the process is the same. Heat the heavy cream in the microwave oven for about 2 minutes and pour it over chopped chocolate. Let it stand, without stirring, for a minute. Then stir gently with a spoon until shiny and smooth.
You can make white chocolate ganache also: use 3 parts white chocolate to 1 part heavy cream.
Colours and flavours can be added, making it very versatile.