Preheat the oven to 350°F (175°C).
Prepare the crust by mixing graham cracker crumbs, cocoa powder, and melted butter in a bowl.
Press the mixture into the bottom of a 9-inch springform pan. Bake for 10 minutes, then cool.
In a large mixing bowl, beat the softened cream cheese and sugar until smooth and creamy.
Add the eggs one at a time, mixing thoroughly after each addition.
Stir in the melted dark chocolate and vanilla extract until fully combined.
Fold in the fresh raspberries gently to avoid breaking them too much.
Pour the cheesecake batter into the cooled crust and smooth the top.
Bake in the preheated oven for 55–60 minutes or until the center is set but still slightly jiggles.
Turn off the oven, crack the door, and let the cheesecake cool in the oven for 1 hour.
Remove the cheesecake from the oven and refrigerate for at least 4 hours or overnight before serving.
