Prepare the Crust

1. Preheat oven to 325°F (165°C).
2. Combine the crushed chocolate cookies and melted butter in a bowl.
3. Press the mixture firmly into the bottom of a 9-inch springform pan. Set aside.

Make the Cheesecake Batter

1. In a large bowl, beat the cream cheese and 1 cup sugar until smooth.
2. Add the eggs one at a time, mixing well after each addition.
3. Mix in the sour cream and vanilla extract.
4. Fold in the melted chocolate until evenly combined.
5. Pour the batter over the prepared crust in the springform pan.

Bake the Cheesecake

1. Bake for 55-60 minutes, or until the center is set but still slightly jiggly.
2. Remove from the oven and cool on a wire rack for 10 minutes.
3. Run a knife around the edge of the pan to loosen the cheesecake, then let it cool for 1 hour longer.
4. Refrigerate the cheesecake overnight.

Prepare the Coconut-Pecan Topping

1. In a medium saucepan, combine the evaporated milk, sugar, beaten egg yolks, and butter.
2. Cook over medium heat, stirring constantly, until the mixture thickens, about 12 minutes.
3. Remove from heat and stir in the vanilla extract, shredded coconut, and chopped pecans.
4. Let the topping cool until it is thick enough to spread.

Assemble the Cheesecake

1. Spread the coconut-pecan topping evenly over the chilled cheesecake.
2. Refrigerate any leftovers.