Here's the recipe I use for ganache:
(from
www.joyofbaking.com)
8 ounces (227 grams) semisweet or bittersweet chocolate, cut into small pieces
3/4 cup (180 ml) heavy whipping cream
2 tablespoons (28 grams) unsalted butter
1 tablespoons cognac or brandy (optional)
***NOTE: I don't use this ... instead, I add a couple of drops of LorAnn Orange Oil ... it adds a really nice, very subtle orange flavor, and really brings out the rich chocolatey flavor. 
Place the chopped chocolate in a medium sized stainless steel bowl. Set aside. Heat the cream and butter in a medium sized saucepan over medium heat. Bring just to a boil. Immediately pour the boiling cream over the chocolate and allow to stand for 5 minutes. Stir with a whisk until smooth. If desired, add the liqueur (or in my case, the orange oil).