Preheat oven to 350 °F (175 °C). Line an 8×8‑inch pan with parchment, letting sides overhang.

In a medium bowl, combine graham cracker crumbs, melted butter, and ¼ cup sugar. Press firmly into the bottom of the prepared pan to form the crust.

Bake crust for 8–10 minutes, then set aside to cool slightly. Lower oven temperature to 325 °F (160 °C).

In a mixing bowl, beat the cream cheese and ½ cup sugar until smooth and creamy. Add eggs one at a time, mixing well after each.

Stir in sour cream and vanilla until just combined.

Pour cheesecake batter over the pre‑baked crust, spreading evenly. Dollop spoonfuls of dulce de leche over the top.

Use a knife or skewer to swirl the dulce de leche into the cheesecake layer for a marbled effect.

Bake for 30–35 minutes, or until the center is set but still slightly jiggly.

Remove from oven and let cool on a wire rack for about an hour. Then refrigerate, uncovered, for at least 4 hours or overnight to fully set.

Once chilled, lift bars from pan using the parchment overhang and cut into squares or bars. Drizzle with extra dulce de leche before serving.