Preheat your oven to 350°F (175°C) and line an 8x8-inch baking dish with parchment paper.

In a large mixing bowl, combine graham cracker crumbs, flour, sugar, and salt. Add cooled melted butter and mix until it resembles wet sand.

Set aside one-third of the crumb mixture for the topping. Press the remaining mixture firmly into the bottom of the baking dish.

In a separate bowl, beat cream cheese until smooth. Gradually add sugar and then incorporate eggs one at a time, followed by lemon juice, zest, and vanilla extract.

Pour the lemon filling over the crust and sprinkle the reserved crumb mixture on top. Bake for 30-35 minutes until the center is set with a slight jiggle.

Cool on the counter for about 1 hour before refrigerating for at least 3 hours.

Once chilled, lift the bars out using the parchment overhang and cut into squares.