If using block chocolate, chop the chocolate into small pieces. You can also scrape it with a serrated knife for easy melting. Place the chocolate in a heat proof bowl. Set aside.
In a separate heat proof bowl or small saucepan, measure the cream.
Double boil it over medium heat until the sides start to bubble.
Turn off the heat. Lift the bowl or saucepan and wipe the bottom dry with a kitchen towel. Pour the hot cream into the chopped chocolate.
Let the cream and the chocolate sit for 2 to 3 minutes. Do not stir.
Once the 2 to 3 minutes is up, gently stir the chocolate and the cream with a rubber spatula or a hand whisk until they are well combined. They will appear separated in the beginner but will come together smoothly with some mixing.
As soon as the mixture becomes smooth, stop mixing. Do not over mixing and it can cause the ganache to split. Overmixing with a whisk will also incorporate too many air bubbles into the ganache which can be unsightly when spread on cakes or cupcakes.
Cover the ganache with a plastic wrap (make sure it touches the surface) to prevent the ganache from forming a skin. Let the ganache cool completely.
If you wish to use the ganache for dipping or dripping (on the sides of a cake), you can use it as soon as it cools down slightly or while it is still warm. Do note that the ganache consistency may be a little too thick for dipping, but good for dripping. Refer to variation notes below if you wish to make thinner dipping consistency ganache.
If you wish to use the ganache for spreading on cakes, refrigerate until it sets and then bring it back to room temperature before using.
To make whipped ganache, let the ganache cool to room temperature and then refrigerate until it sets firm. Bring back to room temperature and then whip it on high speed for about 2 to 3 minutes until it turns light and fluffy before using.