Preheat your oven to 175°C (350°F). Line a 9x13 inch baking pan with parchment paper, leaving overhang on the sides for easy removal.
Crush the graham crackers into fine crumbs using a food processor or by placing them in a zip-top bag and smashing with a rolling pin. Mix the crumbs with melted butter and sugar until well combined, creating a crumbly mixture.
Press this mixture firmly into the bottom of your prepared pan, creating an even crust. Bake for about 10 minutes or until golden and set. Remove from the oven and let cool slightly.
In a large bowl, beat the softened cream cheese with sugar using an electric mixer or whisk until the mixture is smooth, creamy, and free of lumps, about 2-3 minutes.
Add the eggs one at a time, beating briefly after each addition until just combined. Mix in the vanilla extract and lemon zest for a bright, citrusy flavor.
Pour the sour cream into the mixture and gently fold it in with a spatula until the filling is glossy and smooth.
Pour the filling over the cooled crust, spreading it evenly with a spatula. Tap the pan gently on the counter to release any air bubbles and ensure a smooth surface.
Bake for 25-30 minutes, or until the edges are golden and the center jiggles slightly when shaken. The top may crack, which is normal.
Remove from the oven and let cool in the pan for 30 minutes. Then, transfer to a wire rack and cool completely at room temperature, about 1 hour.
Refrigerate uncovered for at least 4 hours or overnight to set the filling fully. Once chilled, cut into small squares with a sharp knife, wiping the blade between cuts for neat slices.
Enjoy these luscious cheesecake bars straight from the fridge, perhaps topped with fresh berries or a drizzle of chocolate for extra indulgence.
