Preheat your oven to 350°F (175°C) and line a 9x9-inch baking pan with parchment paper, leaving an overhang for easy removal.
In a mixing bowl, combine the graham cracker crumbs and melted butter. Stir until the mixture resembles wet sand.
Press the crumb mixture firmly into the bottom of the prepared pan to form the crust. Bake for 8–10 minutes, then set aside to cool.
In a large bowl, beat the softened cream cheese and sugar with a hand or stand mixer until smooth and creamy.
Add the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.
Pour the cheesecake mixture over the cooled crust, spreading it evenly.
Drizzle the warmed Nutella on top in dollops. Use a knife or toothpick to swirl the Nutella into the cheesecake layer for a marbled effect.
Bake for 25–30 minutes, or until the center is set and the edges are lightly golden.
Let the bars cool at room temperature before refrigerating for at least 2 hours.
Once chilled, lift the bars out of the pan using the parchment overhang. Slice into squares and serve.
