1) To make the cookies: Place the rum or juice and pineapple in a small microwave-safe bowl and cover. Microwave on high for about 1 minute, stir, then set aside to cool to room temperature.
2) Preheat the oven to 375°F. Lightly grease (or line with parchment) two baking sheets.
3) Beat together the butter, brown sugar, coconut milk powder, pineapple flavor, baking powder, and salt until fluffy.
4) Scrape the bottom and sides of the bowl, then beat in the egg.
5) Mix in the flour, dried pineapple (with any unabsorbed liquid), and coconut.
6) Drop the dough by tablespoonfuls onto the prepared pans.
7) Bake the cookies for 12 to 14 minutes, until they're lightly browned on the bottom.
8) Remove from the oven, and let them cool on the pans for 5 minutes, until firm, then transfer to cooling racks.
9) While the cookies cool, make the glaze: Sift together the coconut milk powder and sugar.
10) Whisk in the juice to make a smooth, thick glaze, about the thickness of molasses. Add an extra teaspoon or two of juice, if necessary, to make the glaze pourable.
11) Drizzle the glaze atop the cookies, sprinkle with toasted coconut, and let set until the glaze hardens.
Yield: about 3 dozen cookies.