Combine graham cracker crumbs, sugar and cocoa powder. Stir in melted butter until well blended.
Press mixture evenly into the bottom and about 1 ½ inches up the side of a 9 ½ to 10 inch spring form pan. Place pan in freezer while assembling the filling.
Rinse raspberries and drain well. Place cap side down on paper toweling and set aside.
Preheat oven to 325˚F.
Beat cream cheese in a large bowl with an electric mixer at low speed until smooth and creamy.
Combine sugar, cocoa and cornstarch; then thoroughly blend into the cream cheese.
Add eggs, one at a time, mixing to incorporate but taking care not to over beat.
Blend in raspberry liqueur.
Pour about half of the batter into the prepared crust.
Add 1 cup of fresh whole raspberries evenly over surface and cover with remaining batter. (Place remaining berries in refrigerator to use later as topping.)
Bake 1 hour 15 minutes or until just barely set in center.
Remove from oven and let cool on a wire rack. While cake is still warm run a thin knife around the edge of the pan but do not remove the spring form side. Let cool completely.
Place in a refrigerator and chill until cold throughout – at least 4 hours and preferably overnight.
To serve, remove sides of pan. Top with remaining berries and garnish with Chocolate curls. Use a vegetable peeler to shave chocolate curls over the top of the berries.