Put the 5 ounces chopped bittersweet chocolate in a heatproof bowl and set aside.

In a small saucepan, heat 1/4 cup (59.5 ml) heavy cream over medium heat until it just comes to a boil, watching carefully so it does not boil over.

Immediately pour the hot cream over the chopped chocolate and let sit undisturbed for about 1 minute to soften the chocolate.

Stir the chocolate and cream with a rubber spatula until the chocolate is completely melted and the mixture is smooth.

Stir in 1 tablespoon softened butter until the ganache is glossy and fully combined.

Transfer the ganache to a bowl and press plastic wrap directly onto the surface to prevent a skin from forming.

Refrigerate the ganache at least 1 hour (or overnight) until it is firm enough to scoop.

Line a baking sheet with wax paper. Use a melon baller or small spoon to scoop and form the chilled ganache into balls, placing each truffle on the prepared sheet.

Finish the truffles with your coating of choice. If dipping in chocolate, chill the truffle balls in the refrigerator or freezer for at least 1 hour (or until thoroughly chilled) before dipping.