To prepare the crust, butter a 12-inch flan pan with a removable bottom and set aside. Put the flour, butter, and shortening in a medium bowl. Using your fingertips, mix the shortening and butter with the flour to form a coarse meal. Stir in the salt, and drizzle about half of the water into the flour mixture. Stir the mixture with a fork. Drizzle in additional water until the dough comes together. Form the dough into a ball, cover it in plastic wrap, and set it aside at room temperature for 15 to 30 minutes. Preheat the oven to 350 degrees. Unwrap the dough and place it on a well-floured work surface. Roll the dough out to a 12-inch circle about 1/4 inch thick. Carefully place the dough in the prepared pan and bake in the oven for about 10 minutes, or just until the dough starts to set. Remove the crust from the oven and set aside to cool. (Do not turn off the oven.)

To prepare the filling, put the coconut and macadamia nuts in the bottom of the cooled tart shell. Put the sugar and water in a medium saute pan and cook over high heat, without stirring, until the sugar starts to brown. When the sugar begins to brown, slowly add the cream, stirring to incorporate. Cook until the cream turns golden, about 5 minutes. Remove the pan from the heat and set aside until the caramel is completely cool. Whisk the egg into the caramel and pour the mixture over the coconut and nuts in the crust. Place the tart in the oven and bake for 20 to 25 minutes, or until the caramel is set. Remove from the oven and let cool before slicing.

Slice and serve warm, or refrigerate and serve chilled.

Per serving: 441 Calories (kcal); 34g Total Fat; (67% calories from fat); 4g Protein; 32g Carbohydrate; 60mg Cholesterol; 105mg Sodium Food Exchanges: 1 Grain(Starch); 0 Lean Meat; 0 Vegetable; 0 Fruit; 6 1/2 Fat; 1 Other Carbohydrates