In a large saucepan, whisk together the egg yolks, evaporated milk, and vanilla extract until well blended. Add in the sugar and butter, cooking over medium heat for 12-15 minutes, stirring constantly, until the mixture thickens and resembles a pudding consistency. Remove from heat and stir in the shredded coconut and toasted pecans. Transfer to a heat-proof bowl and refrigerate until completely cooled.

Preheat the oven to 325°F (163°C). Grease the sides and line the bottom of a 9-inch (23 cm) springform pan with parchment paper. In a small bowl, mix the Oreo crumbs with the melted butter. Press the mixture firmly into the bottom and up the sides of the pan. Bake for 8-10 minutes, then allow to cool. Wrap the pan’s exterior with aluminum foil to protect it from the water bath, and set it aside.

Lower the oven temperature to 300°F (148°C). In a large mixing bowl, combine the cream cheese, sugar, cocoa powder, and flour, beating on low speed until smooth. Add the sour cream and vanilla extract, continuing to mix on low speed. Slowly incorporate the melted German chocolate in two portions, ensuring even mixing. Add the eggs one at a time, mixing slowly and scraping down the sides of the bowl as needed to achieve a smooth batter.

Pour about 1 cup of the cheesecake filling over the cooled crust and spread it evenly. Drop spoonfuls of about 1 1/2 cups of the coconut-pecan topping over the cheesecake filling, ensuring an even layer. Gently pour the remaining cheesecake batter over the topping layer, taking care not to disturb the topping too much.

Place the springform pan into a larger roasting pan, filling the outer pan with warm water until it reaches halfway up the sides of the springform pan. Bake for 1 hour 25-30 minutes. The center should be set but slightly jiggly. Turn off the oven and leave the cheesecake inside with the door closed for 30 minutes. Then, crack the oven door and let the cheesecake cool for another 30 minutes.

Remove the cheesecake from the oven and water bath, then refrigerate for 5-6 hours or overnight until firm. Once fully cooled, remove from the springform pan and transfer to a serving plate. Top with the remaining coconut-pecan topping and drizzle with chocolate ganache or sauce, if desired. Store in an airtight container in the fridge and enjoy within 4-5 days.