In a saucepan heat 1/2 cup heavy cream until hot. Chop 8 oz. semi-sweet chocolate and 4 oz. German sweet baking chocolate; add to cream. Whisk until chocolate begins to melt. Whisk in 3 T unsalted butter until melted; whisk in 1 T rum flavoring. Pour into bowl. Cover and chill 2 hours or overnight. Let mixture stand at room temperature for 25 minutes. Scoop out mixture onto baking sheet with large melon-ball scoop. Dust hands with cocoa powder; roll portions into balls. (Note: Even if rolled quickly, truffle mixture will melt and make hands sticky.) Roll in desired coatings; refrigerate until serving. (Coconut flakes pecans, and powdered sugar for toppings) Makes about 4 dozen.
