Preheat oven to 325°F (165°C). Combine crushed chocolate cookies and melted butter. Press into the bottom of a 9-inch springform pan. Set aside.
Beat cream cheese and 1 cup sugar until smooth. Add eggs, one at a time, fully incorporating after each addition. Mix in sour cream and vanilla extract. Fold in melted chocolate. Pour over crust in springform pan.
Bake for 55-60 minutes, or until set and slightly jiggly in the center. Cool on a wire rack for 10 minutes, then run a knife around the edge of the pan to loosen; cool 1 hour longer. Refrigerate overnight.
For the topping, combine evaporated milk, 1 cup sugar, beaten egg yolks, and butter in a saucepan. Cook over medium heat until thickened, about 12 minutes. Remove from heat; stir in vanilla, coconut, and pecans. Cool until thick enough to spread.
Spread topping over cheesecake before serving. Refrigerate leftovers.
