Preheat your oven to 325°F (160°C) and grease a 9-inch springform pan, then wrap the outside with aluminum foil to avoid any water seeping in while baking.
In a bowl, combine the chocolate cookie crumbs, sugar, and melted butter, then press the mixture firmly into the bottom of the prepared springform pan and bake for about 10 minutes, then remove and set aside to cool.
In a large bowl, beat the softened cream cheese and sugar together until smooth, add in the vanilla extract and mix until combined, then beat in the eggs one at a time, making sure to mix well after each addition.
Gently fold in the cocoa powder and sour cream until you achieve a velvety texture.
Carefully fold in the fresh raspberries, making sure not to crush them too much.
Pour the filling over the crust and smooth the top, then place the springform pan in a larger baking dish filled with about an inch of hot water and bake for 55 to 70 minutes or until the center is set but still slightly jiggly.
Turn off the oven and let the cheesecake cool in the oven for about an hour before transferring it to a wire rack to cool completely, then refrigerate for at least four hours, preferably overnight.
Carefully release the springform pan and garnish with additional raspberries and chocolate shavings if desired.