Prepare the crust: Preheat your oven to 325°F (163°C). In a bowl, combine the graham cracker crumbs, sugar, and melted butter. Stir until well combined and the crumbs are evenly coated. Press the mixture firmly into the bottom of an 8×8-inch baking dish lined with parchment paper. Bake for 8-10 minutes or until the crust is lightly golden. Remove from the oven and set aside to cool.

1. Make the cheesecake filling: In a large mixing bowl, beat the softened cream cheese and sugar until smooth and creamy. Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract, lemon juice, and lemon zest. Finally, mix in the sour cream until smooth. Set aside.
2. Prepare the cranberry swirl: In a small saucepan, combine the cranberries, sugar, water, and lemon juice. Cook over medium heat for 8-10 minutes, stirring occasionally, until the cranberries burst and the mixture thickens. Remove from heat and let it cool slightly.
3. Assemble the bars: Pour the cheesecake filling over the cooled graham cracker crust, spreading it evenly. Drop spoonfuls of the cranberry mixture over the cheesecake filling, then use a toothpick or knife to swirl the cranberry mixture into the cheesecake, creating a marbled effect.
4. Bake the bars: Bake in the preheated oven for 30-35 minutes or until the edges are set and the center is slightly jiggly. Let the bars cool completely in the pan on a wire rack.
5. Chill and serve: Once cooled, refrigerate the bars for at least 4 hours or overnight to allow them to set completely. Once chilled, cut into squares and serve.