Preheat the oven to 400°F (205°C) and lightly grease a 9×13-inch baking dish.

In a medium bowl, stir together the flour, salt, vegetable oil, and water until a soft dough forms.

Press the dough evenly into the bottom of the prepared baking dish.

Prick the crust all over with a fork.

Bake for 10–15 minutes, or until lightly golden. Let the crust cool completely.

In a medium bowl, whisk together the half-and-half and egg yolks.

In a saucepan over medium heat, whisk together the granulated sugar and cornstarch.

Slowly whisk in the egg mixture.

Continue whisking constantly until the mixture thickens into a smooth pudding.

Remove from the heat and stir in the butter, flaked coconut, and coconut extract.

Spread the warm filling evenly over the cooled crust.

Let cool slightly, then refrigerate for about 1 hour until chilled.

In a chilled bowl, beat the heavy whipping cream until it begins to thicken.

Add the granulated sugar and vanilla extract, then continue beating until soft peaks form.

Spread the whipped cream evenly over the chilled coconut filling.

For the optional toasted coconut, reduce the oven to 325°F (163°C).

Spread the remaining coconut onto a baking sheet and toast for 5–10 minutes, stirring frequently until lightly golden.

Cool completely, then sprinkle generously over the whipped topping.

Refrigerate until ready to serve, then slice into bars.