Place finely chopped chocolate into a glass or metal bowl.
Scald the cream by bringing it just barely to a simmer. Pour over chopped chocolate.
Cover bowl with plastic wrap and let stand 2 mins. Stir gently with a spatula until combined and smooth.
Place plastic wrap directly on the surface of the ganache. Allow to cool and thicken before using. Do not refrigerate.
Firm Filling/Frosting:
Let ganache firm up overnight at room temperature. Use as is as as a filling and/or frosting.
Drip/Soft Filling/Whipped Ganache/Glaze:
Allow ganache to cool completely and thicken slightly before using as a drip. I let mine cool and thicken overnight, then warm it in the microwave for 3-5 seconds before using.* Note that the amounts shown are enough to make a drip. You will need to increase the amounts to make a filling, whipped ganache, or glaze.
Notes
The volume of ganache for the filling/frosting should make enough to fill and frost a two layer 8" cake.The volume of ganache for the drip is enough to do a drip on a 6" cake.If you want to do a glaze all over a cake or cake roll, use the Drip proportions but increase the amounts. Pour the glaze over a fully frosted chilled cake (place a cooling rack on top of a parchment-lined baking sheet and place the cake on that before pouring the ganache over -- makes for easier cleanup).