Preheat the oven to 325°F (163°C) and line an 8x8-inch baking pan with parchment paper.

In a bowl, combine the graham cracker crumbs, melted butter, and sugar. Press the mixture firmly into the bottom of the prepared pan.

Bake the crust for 8–10 minutes, then set aside to cool slightly.

In a small saucepan, combine the raspberries, sugar, and lemon juice. Cook over medium heat until the berries soften.

Mix the cornstarch with the water, stir it into the raspberry mixture, and cook for 1–2 minutes until thickened. Strain through a fine-mesh sieve if desired and let cool.

In a large bowl, beat the cream cheese and sugar until smooth.

Add the eggs one at a time, mixing just until incorporated. Stir in the vanilla extract and sour cream.

Pour the cheesecake filling over the cooled crust and spread evenly.

Spoon small dollops of the raspberry sauce over the filling and use a knife or skewer to create decorative swirls.

Bake for 35–40 minutes, or until the edges are set and the center has a slight jiggle.

Cool completely, then refrigerate for at least 4 hours or overnight before slicing into bars.