In large heatproof bowl set over saucepan of hot (not boiling) water, heat chocolate, stirring, until half is melted. Remove from heat.
Meanwhile, in saucepan, heat cream with butter just until butter melts and bubbles form around edge of pan. Pour over chocolate; whisk until smooth. Whisk in vanilla and coconut extract. Cover and refrigerate until firm, about 2 hours.
Using melon baller or teaspoon, drop by rounded teaspoonfuls onto 2 waxed paper-lined baking sheets. Gently roll each to round off completely. Freeze until hard, about 1 hour. (Make-ahead: Cover and freeze for up to 1 day.).
Coating: Toast coconut on baking sheet in 375°F (190°C) oven, stirring twice, until light golden, 10 minutes. Let cool.
In heatproof bowl set over saucepan of hot (not boiling) water, melt half of the chocolate, stirring. Remove from heat and let cool slightly. Remove 1 pan of the truffles from freezer; using 2 forks, dip each into chocolate, tapping forks on edge of bowl to remove excess. Roll in coconut. Return to waxed paper-lined baking sheet. Refrigerate until coating is hardened, 2 hours.
In clean bowl, repeat with remaining chocolate, truffles and coconut. (Make-ahead: Layer between waxed paper in airtight container; refrigerate for up to 1 week or freeze for up to 3 months.) Place in paper candy cups.
Tip: If all of the chocolate does not melt after hot cream mixture has been added, place bowl over saucepan of hot (not boiling) water and whisk until smooth.