Prepare the Crust:
Preheat oven to 325°F (163°C).
In a bowl, mix graham cracker crumbs, sugar, and melted butter until combined.
Press the mixture into the bottom of a 9-inch springform pan.
Bake for 10 minutes, then set aside to cool.
Make the Raspberry Swirl:
In a small saucepan over medium heat, combine raspberries, sugar, cornstarch, and lemon juice.
Cook until the raspberries break down and the mixture thickens (about 5 minutes).
Strain through a fine-mesh sieve to remove seeds. Set aside to cool.
Prepare the Cheesecake Filling:
In a large bowl, beat the cream cheese and sugar until smooth.
Add eggs, one at a time, mixing after each addition.
Mix in sour cream, lemon juice, lemon zest, and vanilla extract until fully combined.
Assemble the Cheesecake:
Pour the cheesecake filling over the cooled crust.
Spoon small dollops of the raspberry sauce on top and use a toothpick or skewer to swirl it into the batter.
Bake the Cheesecake:
Place the cheesecake in the oven and bake for 50-60 minutes, until the edges are set but the center still has a slight jiggle.
Turn off the oven, crack the door open, and let the cheesecake cool inside for 1 hour.
Chill and Serve:
Refrigerate the cheesecake for at least 4 hours (preferably overnight).
When ready to serve, remove from the springform pan and garnish with fresh raspberries and lemon zest.