Directions

1. Preheat the oven to 350 degrees. Spread coconut on a rimmed baking sheet, and toast until golden brown, 6 to 8 minutes, tossing every 2 minutes to ensure even browning. Remove from oven; transfer to a plate to cool.
2. In a large mixing bowl, combine flour and sugar, and add half the toasted coconut. Using two knives or a pastry cutter, cut the butter into the flour-coconut mixture until it resembles coarse meal. Pat mixture into a 9-by-13-inch pan, and bake until golden, 20 to 25 minutes. Allow to cool slightly.
3. Meanwhile, beat together egg yolks and condensed milk with a whisk until thick. Gradually beat in lime zest and juice. Pour into cooled crust, sprinkle with remaining toasted coconut, and bake until just hot, 6 to 8 minutes. Cool completely, then chill until ready to serve. Cut into six 2 1/3-inch rows; cut rows on a diagonal to form diamonds. Before serving, sprinkle with confectioners' sugar, and garnish with lime zest, if desired.