Preheat the oven to 350 degrees. Line an 8×8" square baking pan with parchment paper or aluminum foil.

Place the graham cracker crumbs, 3 tablespoons sugar, and pinch of salt in a small bowl and stir to combine. Add the melted butter and stir until the crumbs are coated well with the butter. Press the crust evenly over the bottom of the prepared baking dish and bake for 10 minutes or until lightly golden brown. Cool on a wire rack while you make the filling. Reduce the oven temperature to 325 degrees.

In a medium bowl, beat the cream cheese and sugar together at medium speed until smooth, about 1 minute. Add the sour cream, eggs, key lime juice, zest, and vanilla, and beat until smooth and well incorporated.

Pour the filling over the prepared crust and bake for 30-40 minutes or until the filling is set but still a bit jiggly in the center (the filling will set more as it cools). Begin checking for doneness after 30 minutes as all oven times vary.

Cool completely on a wire rack, then chill in the refrigerator for a minimum of 3 hours.

Once cooled, grab the ends of the foil and lift the cheesecake from the pan. Cut into bars with a very sharp knife, cleaning the knife with warm water in between slices to get a clean slice. Pipe or dollop whipped cream on top of the bars, then serve and enjoy!