Fruit and vegetable purees can be substituted for all or part of the cream in preparing ganache. As purees do not contain fats, butter is often added to the ganache formula when purees are used. As a general guideline, the amount of butter should equal 50 percent of the nonfat liquid. For example, if using 3.5 oz/100 g fruit puree, add 1.8 oz/50 g of butter to the formula. When the ganache has cooled to 97&F/37&C, mix in the butter using an immersion blender.
If using fruit or vegetable purees to replace cream entirely, the amount of chocolate in the formula may need to increase to compensate for the increase in water from the puree. The final texture of this ganache will be very firm and lack the characteristic creamy mouthfeel of more traditional ganaches.