Microwave first 2 ingredients and 1 1/2 cups cream in a medium-size microwave-safe bowl at MEDIUM (50% power) 1 minute; stir. Microwave 3 to 3 1/2 more minutes or until melted, stirring every 30 seconds. Stir in up to 1/4 cup cream, 1 Tbsp. at a time, until desired consistency is reached.
Note: Reserve 3/4 cup ganache to serve with trifle. Just before serving, reheat reserved Chocolate Ganache in a microwave-safe bowl at MEDIUM (50% power) for 30 to 60 seconds, stirring every 30 seconds.