Step 1: Prepare the Crust

1. Preheat your oven to 325°F (165°C). Line a 9×9-inch baking dish with parchment paper, leaving an overhang on two sides for easy removal.
2. In a medium bowl, mix the graham cracker crumbs, granulated sugar, and melted butter until evenly combined. The mixture should resemble wet sand.
3. Press the crust mixture firmly and evenly into the prepared baking dish. Use the bottom of a glass or measuring cup to compact it.
4. Bake the crust for 8–10 minutes, then set aside to cool slightly while you prepare the filling.

Step 2: Make the Cheesecake Filling

1. In a large mixing bowl, use an electric mixer to beat the softened cream cheese until smooth and creamy, about 2 minutes.
2. Add the granulated sugar and mix until well combined.
3. Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next.
4. Mix in the vanilla extract, followed by the dulce de leche, until the filling is smooth and evenly combined.

Step 3: Assemble the Cheesecake Bars

1. Pour the cheesecake filling over the cooled crust, spreading it evenly with a spatula.
2. Warm the remaining 1/4 cup of dulce de leche in the microwave for 10–15 seconds to make it easier to drizzle.
3. Spoon small dollops of the warmed dulce de leche onto the surface of the cheesecake filling. Use a knife or skewer to swirl the dollops into the filling, creating a marbled effect.

Step 4: Bake the Cheesecake Bars

1. Bake in the preheated oven for 40–50 minutes, or until the edges are set and the center jiggles slightly when shaken. Avoid overbaking, as the bars will firm up as they cool.
2. Allow the bars to cool at room temperature for 1 hour.

Step 5: Chill and Slice

1. Transfer the cooled bars to the refrigerator and chill for at least 4 hours, or overnight, to set completely.
2. Once chilled, use the parchment paper overhang to lift the bars out of the pan. Place them on a cutting board and slice into 12 squares using a sharp knife. Wipe the knife clean between cuts for neat slices.

Step 6: Serve

Serve the bars chilled or at room temperature. Optionally, drizzle with additional dulce de leche or sprinkle with a pinch of sea salt for garnish.