I don't know who needs to hear this, but the magic ratio for ganache (a firm one, such as you would use to make truffles or enrobe a cake) is 1 tablespoon of heavy cream per one ounce of chocolate. Chop the chocolate (or use chips), then boil the cream, immediately pour it over the chocolate, and whisk until smooth. People get so impressed whenever I make ganache but it is literally so easy. When it's freshly made you can dip fruit or cookies in it or use it to fill doughnuts, and if you let it cool and harden somewhat you can roll spoonfuls into balls to make truffles or use it as a filling for sandwich cookies. Also if you're feeling gremlinous you can just eat it with a spoon.
Important addendum I discovered last year: the above is the magic ratio specifically if you are using dark chocolate (which I always was because it's my favorite). The process is the same, but for milk chocolate the ratio is 1 tablespoon of heavy cream per 1.5oz of chocolate and for white chocolate it's 1 tablespoon of heavy cream per 2oz of chocolate. This is because milk and white chocolate have less chocolate per chocolate so they behave differently. Now you know. Go forth and make delicious ganaches.
