Silken, chocolatey ganache creates a glistening dessert topping that is as mouthwatering as it is beautiful to look at. A perfect ganache is smooth, creamy and easily drizzled -- but it's not always easy to achieve. Ganache is an emulsion of cream and chocolate that can turn into a grainy soup if stirred too quickly or worse, can break or separate if the mixing temperatures are wrong. However, it is possible to repair ganache and present a beautiful dessert to your guests.
Divide the broken ganache in half and place in two separate bowls. Place one bowl over a double boiler that is simmering on medium heat and the other over a bowl of ice.
Gently stir both halves of the ganache and place a candy thermometer in each. Be very careful not to let any water from the double boiler or the ice get into the ganache; this will ruin it beyond repair.
Check the thermometers. Once the ganache over the double boiler has reached 54.4 degrees C and the ganache over the ice has reached 15.6 degrees C, slowly pour the hot ganache into the cold ganache, mixing gently with a spatula to combine the two mixtures. This brings the ganache to the optimum working temperature of 32.2 degrees C.
When making the ganache, if you see the fat begin to separate from the cream while mixing, add 1 tsp cold double cream and mix it in while lowering the temperature of your double boiler -- don't add too much cream, because this can cause the ganache to freeze.