Preheat oven to 325°F with racks in upper and lower thirds.  Line 2 baking sheets with parchment paper.

Place 2 2/3 cups (7 ounces) flaked coconut and the confectioners' sugar in a food processor and whirl for 30 seconds.  Add the rest of the ingredients except for the chocolate and remaining coconut.  Whirl until the coconut is well chopped and the batter is creamy, scraping down inside of processor once.

Pour the remaining 1 3/4 cups (5 ounces) of flaked coconut into a medium bowl.  Drop a generous tablespoonful of dough into the bowl and gently toss to coat with coconut.  Roll into a ball between your palms, then roll in the coconut again and set on the prepared baking sheet. Repeat with remaining dough and flaked coconut, setting cookies about 1/2 inch apart (they don't spread much).

Bake until golden around the top and edges, switching position of pans halfway through, 25 to 30 minutes total.  Slide parchment with cookies onto a cooling rack to cool completely.

Break or chop chocolate into small chunks, put in a small microwave-safe bowl, and heat in 20-second bursts until almost melted.  Stir to melt completely.  If very liquidy, let cool until as thick as sour cream.

Line a baking sheet with waxed paper or parchment paper.  Hold one cookie at a time by the top and dip the bottom into the melted chocolate about 1/2 inch up the side of the cookie.  Set on the prepared baking sheet and chill for 1 hour to set the chocolate.

Macaroons can be stored for up to 2 weeks, chilled in an airtight container.