How to Make It
In a bowl, stir together the flour, sugar and salt. Using a pastry cutter or your fingers, cut in the butter until it resembles coarse crumbs. Sprinkle the ice water on top and stir just until combined. Shape the dough into a ball and pat out to an 8-inch disk. Wrap in wax paper and refrigerate for at least 1 hour or overnight.
On a lightly floured surface, roll out the dough to a 16-by-18-inch rectangle, about 1/4 inch thick. Using a 5-inch round pastry cutter, cut out 8 circles. Press the circles into eight 4-inch tartlet pans with removable bottoms. Trim the tops of the pastry shells and refrigerate them.
Preheat the oven to 375°. In a small saucepan, melt the butter with the vanilla bean over low heat. Remove from the heat and, using a small knife, scrape the seeds from the vanilla bean into the butter. Discard the bean or reserve it for another use.
Set the pastry shells on a large baking sheet and divide the macadamia nuts and white chocolate chunks evenly among them. In a medium bowl, mix the corn syrup with the brown sugar and eggs. Stir in the vanilla butter and walnut liqueur and pour the mixture over the nuts and chocolate to fill the tartlet shells. Bake in the center of the oven for about 40 minutes, or until the tops are puffed and lightly browned. Let cool slightly on a rack. Remove the sides of the pans. Serve the tartlets warm or at room temperature with vanilla ice cream.