Preheat the oven to 325°F (160°C). Grease the springform pan and set it aside.
To make the crust, combine the graham cracker crumbs, sugar, and melted butter in a bowl. Mix until well combined. Press this mixture evenly into the bottom of the prepared springform pan.
In a mixing bowl, beat the softened cream cheese with an electric mixer until smooth. Gradually add the sugar, followed by the sour cream, and mix until completely combined.
Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and the melted chocolate until fully incorporated.
Pour the cheesecake filling over the crust in the springform pan. Smooth out the top with a rubber spatula.
Bake in the preheated oven for about 60 minutes, or until the edges are set and the center is slightly jiggly.
Allow the cheesecake to cool in the pan for about 1 hour before refrigerating for at least 4 hours, preferably overnight.
While the cheesecake is cooling, prepare the coconut-pecan topping. In a saucepan over medium heat, combine the evaporated milk, sugar, butter, and egg yolks. Cook while stirring constantly until the mixture thickens (about 10 minutes).
Remove from heat and stir in the shredded coconut, chopped pecans, and vanilla extract. Let it cool to room temperature.
Once the cheesecake is chilled and set, spread the coconut-pecan topping evenly over the surface.