Preheat the oven to 325 degrees Fahrenheit.

Spread the slivered almonds on a baking sheet.

Toast the almonds in the preheated oven for 7 to 10 minutes, stirring occasionally, until golden brown.

Cool the toasted almonds.

Set aside 1/2 cup of the toasted almonds for garnish.

In a food processor, combine the remaining toasted almonds and sugar.

Pulverize the almonds and sugar until finely ground.

Add the torn white bread to the food processor.

Pulse the machine until the bread is reduced to fine crumbs.

Drizzle the melted butter into the food processor.

Pulse to mix all ingredients thoroughly.

Evenly pat the almond-bread mixture over the bottom and sides of a 9-inch tart pan with a removable bottom.

Refrigerate the crust for several minutes to set.

Twist a corkscrew into two of the coconut's eyes to drain the trapped liquid into a cup, straining if necessary.

Place the coconut on a baking sheet and bake for about 15 minutes to loosen the flesh from the shell.

Crack the coconut into several pieces using a hammer.

Use a small knife or screwdriver to pry the flesh from the shell.

Peel away the dark brown skin from the coconut flesh using a paring knife or vegetable peeler.

Grate the coconut into medium-fine shreds using a food processor or grater.

Measure out 2 1/2 cups of grated coconut for the pie.

Reserve the remaining grated coconut for garnish.

Raise the oven temperature to 350 degrees Fahrenheit.

In a small saucepan, combine the coconut water, heavy cream, and sugar.

Simmer over medium heat, stirring frequently, until reduced to 1 cup (10 to 15 minutes).

Pour the reduced coconut cream mixture into a large bowl.

Stir in the 2 1/2 cups of grated coconut, reserved 1/2 cup of toasted almonds, egg yolks, and vanilla.

Set the prepared crust onto a baking sheet.

Scoop the coconut filling into the crust.

Bake in the middle of the oven until set and lightly browned on top (30 to 35 minutes).

Cool the pie on a wire rack.

While the pie is baking, toast the reserved coconut on a baking sheet in the oven, stirring occasionally, until nicely browned (7 to 10 minutes).

Cool the toasted coconut.

Cool the pie completely and slice.

Serve with sour cream and toasted coconut.