Preheat your oven to 325°F. Lightly spray the bottom of an 8-inch by 8-inch baking pan. If you want very clean cuts on the bars, feel free to line the pan with foil for easier removal.
In a medium bowl, combine the graham cracker crumbs, granulated sugar, and kosher salt. Stir these together until they’re well mixed. Then, add the melted butter to the mixture. Stir until everything is thoroughly combined and the crumbs are moistened.
Press the crumb mixture evenly into the bottom of the prepared pan. Use the back of a measuring cup or your fingers to pack it down firmly. Bake this crust in the preheated oven for 10 to 12 minutes. It should become fragrant and slightly golden. Once done, set it aside on a wire rack to cool completely.
While the crust cools, prepare the cheesecake filling. In a large mixing bowl, use an electric mixer to cream the cream cheese and sugar together on medium-high speed until smooth and creamy, about 1 to 2 minutes. Be sure to scrape down the sides of the bowl to ensure everything is well combined.
Next, add the eggs, sour cream, lemon juice, and lemon zest to the mixture. Beat on medium speed until everything is just combined. You don't want to overmix, as this can lead to cracks in your cheesecake.
Spread the cheesecake mixture evenly over the cooled crust. Gently tap the pan on the counter a few times to settle the filling and release any air bubbles.
Now it’s time to add the raspberries. Scatter them on top of the cheesecake filling, pressing them down slightly so they’re partially submerged. This will ensure that each bar has a lovely raspberry surprise!
Place the pan back in the oven and bake for about 40 minutes. The cheesecake should be set but still slightly wobbly in the center. You’ll notice the edges might turn a light golden brown. Once done, remove it from the oven and let it cool completely on a wire rack.
After cooling, refrigerate the cheesecake for at least 3 hours to chill thoroughly and firm up. If you can, let it sit overnight for the best texture and flavor.
To serve, slice the cheesecake into individual bars. If you lined the pan with foil, gently lift the cheesecake out using the overhang, then place it on a cutting board. Use a sharp knife dipped in warm water for clean cuts. Wipe the knife between slices for perfectly neat bars.