01 - Preheat oven to 350°F. Line a 9x9-inch baking pan with parchment paper, allowing overhang for easy removal.
02 - Combine graham cracker crumbs, sugar, and melted butter in a medium bowl. Press mixture firmly into the bottom of the prepared pan. Bake for 8 minutes, then allow to cool slightly.
03 - In a small saucepan, combine raspberries, sugar, cornstarch, and water. Cook over medium heat, stirring and mashing berries until thickened, about 4 to 5 minutes. Strain through a fine mesh sieve to remove seeds and set aside to cool.
04 - Beat cream cheese and sugar in a large bowl until smooth and creamy. Add eggs one at a time, mixing well after each addition. Incorporate sour cream, flour, lemon zest, lemon juice, and vanilla extract until fully combined.
05 - Spread the cheesecake mixture evenly over the cooled crust.
06 - Drop spoonfuls of raspberry sauce over the cheesecake layer. Gently swirl with a toothpick or knife to create a marbled effect.
07 - Bake for 30 to 32 minutes, until the center is just set and slightly jiggly. Cool to room temperature, then refrigerate for at least 2 hours before slicing.
08 - Lift bars from pan using parchment overhang and cut into 16 squares.