Step 1

In a blender or food processor, blend the vanilla wafers into a sandy consistency.

Step 2

Mix in the melted butter and salt until the cookie crumbs are completely saturated and have deepened in color.

Step 3

Press the cookie crust into an 11x7-inch baking dish in an even layer and freeze. If you don't have an 11x7-inch dish, use any square or rectangle dish with a 10-cup (2.5 qt) volume.

Step 4

Add the unsweetened coconut flakes to a large saucepan set over medium heat. Toast the flakes, stirring occasionally so they don't burn. Remove them from the pan when they are golden brown.

Step 5

Add 1 cup of the toasted coconut flakes, the condensed milk, evaporated milk, coconut milk, salt, brown sugar, granulated sugar, and flour to a heavy-bottomed saucepan set over medium heat. Stir until everything is combined and the milk has thickened, about 5 minutes.

Step 6

Take the milk mixture off the heat and let it steep for 20 minutes. Use a fine-mesh sieve to strain the coconut flakes from the milk mixture and discard. Add the milk mixture back to the pan and set over medium heat.

Step 7

In a small bowl, add the water to the egg yolks. Mix in the cornstarch to create a slurry, then add it to the milk mixture in the pan. Cook over medium heat, stirring constantly until the custard bubbles in spurts.

Step 8

Take the pan off the heat and add the butter and vanilla extract. Mix until the butter dissolves.

Step 9

Strain the mixture through a fine-mesh sieve directly into the chilled crust. Refrigerate until set, about 2 to 3 hours.

Step 10

Top with whipped cream topping and sprinkle the whipped cream with the remaining 1/2 cup of toasted coconut flakes.