To prepare the tart shell: In a food processor, combine granulated sugar, flour, and salt; process briefly to mix. Add butter; process 5 seconds. With machine on, add ice water, processing just until dough begins to come together. Press a bit of dough between your fingers. If dough seems dry, gradually add more ice water, a few drops at a time.
On a lightly floured surface, roll dough into a 6-by 16-inch rectangle about ¼ inch thick. Ease dough into a 4- by 14-inch tart pan. (Or, roll dough into an 11-inch diameter circle and use a 9-inch-diameter tart pan with removable bottom.) Pat some of the overhang back in around the edge to make the sides of the tart shell a bit thicker than the bottom. Trim off any remaining overhang. Refrigerate or freeze unbaked tart shell until firm, about 30 minutes.
To bake the tart shell partially, preheat oven to 350°. With a fork, prick bottom and sides of dough all over. Fit a 12- to 14- inch square of parchment paper (or a double thickness of aluminum foil with a few holes poked in it) snugly against pastry in pan. Bake until edges are golden brown, about 15 minutes. Carefully lift out parchment. Bake until bottom of tart shell appears dry but not browned, about 5 minutes. Let cool on a wire rack.
To assemble and bake the tart: Preheat oven to 350°. Spread macadamias on a baking sheet or in a shallow pan. Bake, stirring once or twice, until lightly browned and fragrant, 5 to 7 minutes. Let cool. Decrease oven temperature to 325°.
Spread coconut on a baking sheet or in a shallow pan. Bake, stirring occasionally, until lightly browned, about 10 minutes. Let cool. Increase oven temperature to 350°.
Spread pecans on a baking sheet or in a shallow pan. Bake, stirring once or twice, until lightly browned and fragrant, 7 to 10 minutes. Let cool. Leave oven set at 350°.
In a small saucepan, melt butter over medium heat. Stir in brown sugar, until completely moistened. Remove from heat and set aside.
In a large bowl, whisk together egg yolks, coconut milk, almond extract, and salt. Whisk in the brown sugar mixture. Stir in macadamias, coconut, and pecans. Scrape mixture into the tart shell and smooth the top with a spatula. Bake until tart is golden brown and just set in the center, about 20 minutes. Let cool slightly. Serve warm or at room temperature.
How to Mend a Broken Tart
If your tart shell cracks on the bottom, make a thick paste of flour and water and use it to seal the crack. Place the shell back in the oven for a few minutes to dry the "glue." – E.L.