Prepare the Raspberry Swirl

Add raspberries, sugar, and lemon juice to a small saucepan. Cook over medium heat for 6–7 minutes until the berries soften and release juices. Strain through a fine mesh sieve to remove seeds. Let cool completely.

 Prepare the Crust

Preheat oven to 325°F (163°C).
Mix graham cracker crumbs, sugar, melted butter, and cocoa powder. Press firmly into the bottom of a 9-inch springform pan. Bake for 8 minutes and set aside.

 Melt the Dark Chocolate

Microwave chopped dark chocolate in 20–30-second intervals, stirring until smooth. Cool slightly.

 Make the Cheesecake Batter

Beat softened cream cheese until smooth. Add sugar and mix until fluffy. Add sour cream, vanilla, and salt.
Beat in eggs one at a time on low speed.
Fold in melted dark chocolate until smooth.

 Assemble the Cheesecake

Pour batter over the crust. Spoon raspberry sauce on top and swirl with a knife or skewer.

Bake

Place the pan inside a larger pan and add hot water to create a water bath.
Bake 55–65 minutes until the edges set and the center jiggles slightly.
Turn off the oven and let the cheesecake rest inside for 1 hour with the door slightly open.

 Chill and Serve

Cool completely, then refrigerate for at least 6 hours or overnight.
Top with raspberries, chocolate shavings, or whipped cream before serving.