Preheat your oven to 325°F (160°C). Line an 8×8-inch or 9×9-inch baking pan with parchment paper, leaving a slight overhang on the sides for easy removal.
In a medium bowl, combine the graham cracker crumbs, sugar, and melted butter. Mix until the crumbs are evenly coated and the mixture resembles wet sand.
Press the crumb mixture firmly into the bottom of the prepared baking pan to form an even layer. Bake for 8-10 minutes or until golden brown. Remove from the oven and set aside to cool while you prepare the cheesecake filling.
2. Make the Cheesecake Filling:
In a large bowl, use a hand mixer or stand mixer to beat the cream cheese and sugar together until smooth and creamy, about 2-3 minutes.
Add the eggs, one at a time, beating well after each addition. Then, add the vanilla extract, sour cream (if using), and flour. Beat until everything is fully combined and the mixture is smooth.
Pour the cheesecake batter over the cooled crust and spread it evenly.
3. Make the Raspberry Sauce:
In a small saucepan, combine the raspberries, sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the raspberries break down and release their juice, about 5-7 minutes.
Once the mixture has thickened slightly, remove it from the heat and let it cool for a few minutes. Then, strain it through a fine mesh sieve to remove the seeds, if desired. Allow the sauce to cool completely.
4. Add Raspberry Swirl:
Drop spoonfuls of the cooled raspberry sauce onto the cheesecake batter. Use a toothpick or a knife to gently swirl the raspberry sauce into the cheesecake, creating a marbled effect.
Bake the cheesecake bars in the preheated oven for 30-35 minutes, or until the center is set but still slightly jiggly. The edges should be golden brown.
5. Cool and Chill:
Remove the cheesecake bars from the oven and let them cool to room temperature. Once cooled, place them in the refrigerator and chill for at least 4 hours or overnight for best results.
6. Serve:
Once chilled, lift the bars out of the pan using the parchment paper overhang. Cut into squares or bars.
Garnish with fresh raspberries, a dusting of powdered sugar, and a sprig of mint if desired.
