Place the chocolate in a heat-proof bowl. Set aside.
Heat the heavy cream until it is simmering. You can heat it on the stove or in the microwave.
Add the butter, if using, to the chocolate and pour the heavy cream evenly on top. Let the warm cream and chocolate sit for 5 minutes minutes. Add the vanilla extract then stir until the chocolate has completely melted. Place a piece of plastic wrap directly on the surface (to avoid condensation) and refrigerate for 1-2 hours. Tip: Pour into a flat shallow dish, such as a 8-inch square baking pan, so the mixture evenly and quickly sets.
Scoop the set truffle mixture into 2 teaspoon-sized mounds. This small cookie scoop is the perfect size. For larger truffles, 1 Tablespoon size mounds. Roll each into balls. This gets a little sticky, so see my tips above.
Roll each into toppings, if desired. Truffles taste best at room temperature!
Cover tightly and store truffles at room temperature for 3-4 days or in the refrigerator for up to 2 weeks.
