Preheat oven to 325°F (163°C). Line an 8x8" pan with parchment paper, leaving an overhang.

Make the crust: Mix graham cracker crumbs, sugar, salt, and melted butter until it resembles wet sand. Press firmly into the bottom of the pan. Bake for 8–10 minutes. Let cool slightly.

Make the raspberry swirl: In a small saucepan, heat raspberries, sugar, and lemon juice over medium heat until raspberries break down. Mash and simmer 2–3 minutes. For a thicker texture, stir in cornstarch and cook for 1 more minute. Strain to remove seeds (optional). Set aside to cool.

Make the filling: Beat softened cream cheese and sugar until smooth. Add vanilla, then eggs one at a time. Mix in sour cream and flour just until combined—don't overmix.

Assemble: Pour the cheesecake filling over the crust and smooth the top. Drop spoonfuls of raspberry puree on top and swirl with a toothpick or skewer.

Bake for 35–40 minutes or until the center is set but still slightly jiggly. Let cool at room temp, then refrigerate for at least 2 hours (overnight is best).

Slice into bars and enjoy!