Position a rack in the middle of the oven. Preheat the oven to 300° F.

Spread the coconut on a baking sheet. Bake for about 10 minutes, stirring once, until the coconut becomes evenly golden. Watch carefully, as the coconut can darken quickly toward the end of baking. Set aside to cool. Increase the oven temperature to 350° F. Line two baking sheets with parchment paper.

Sift the flour, baking powder, salt, and cinnamon into a medium bowl and set aside.

In a large bowl, using an electric mixer on medium speed, beat the butter and brown sugar until smooth and fluffy, about 1 minute. Stop the mixer and scrape the sides of the bowl as needed during mixing. Add the egg, vanilla, and almond extract and mix until blended, about 1 minute. On low speed, add the flour mixture, mixing just until it is incorporated. Use a large spoon to stir in 1½ cups of the toasted coconut.

Divide the dough into 2 portions and pat each into a flat rectangle. Cut 2 large sheets of wax paper, and roll one portion of dough between the wax paper into a 7½-by-12-inch rectangle that is about ¼ inch thick. Remove the top piece of wax paper and discard it. Trim the edges of the dough slightly to even them. Cut the dough into 9 rectangles that measure about 4 by 2½ inches. Lift the cookies, on the wax paper, and place cookie side down on a prepared baking sheet. Lift off the wax paper and use a metal spatula to separate and spread out the cookies so they are about 2 inches apart. Holding a fork so the underside is facing down, draw the tines of the fork down the length of each cookie to cover it with parallel lines. Repeat with the second rectangle of dough.

Bake one sheet at a time until the edges and bottoms of the cookies are lightly browned, about 15 minutes. The centers should remain light in color. Cool the cookies for 5 minutes on the baking sheets, then use a wide metal spatula to transfer them to a wire rack to cool completely.

Put the white chocolate in a heatproof container or top of a double boiler, and place it over, but not touching, a saucepan of barely simmering water (or the bottom of the double boiler). Stir until melted and smooth. Remove from the water and let the white chocolate cool and thicken slightly, about 10 minutes.

Use a pastry brush to paint a 1-inch border of melted white chocolate across one narrow end of each cookie. Sprinkle the remaining toasted coconut on the white chocolate. Let the cookies sit at room temperature until the white chocolate is firm, about 1 hour. Or, to speed the firming of the white chocolate, refrigerate the cookies uncovered for about 15 minutes, then remove from the refrigerator.