Melt 1 pound of chocolate, slowly stirring, in a double boiler. Warm the cream in a large saucepan but do not scorch. Remove the chocolate from the heat, cool slightly, then combine with the heavy cream. Stir the butter into the chocolate cream mixture and refrigerate until firm but still pliable, about 20 minutes. Transfer the chocolate to a pastry bag fitted with a large straight tip and pipe into teaspoonsize mounds onto a waxed paper covered cookie sheet, or use a spoon to dole out teaspoonsize mounds. Refrigerate the entire pan until the chocolate is hard to the touch.
When the chocolate is sufficiently firm (this can be done a day or 2 ahead) remove the chocolate from the refrigerator and, working quickly to prevent melting, roll the chocolate mounds into balls, then chill the balls again until firm.
In a food processor fitted with a metal blade, pulse the coconut briefly to make it a little finer so that it will adhere better to the truffles. When firm, roll each truffle in the coconut, pressing firmly to make sure the coconut sticks. At this point you can refrigerate the truffles for as much as a day, until you are ready to dip them.
Melt the remaining chocolate in the double boiler. Remove the double boiler from the heat and using a wire dipping spoon, or a regular teaspoon and your hands in latex gloves, dip each coconut covered truffle briefly into the melted chocolate. Place on a cake rack set over a cookie sheet until dry, and refrigerate until firm. You may scrape up any chocolate that has dripped on the cookie sheet and return it to the dipping pot for more dipping. The truffles will keep for several weeks if refrigerated in a covered container.