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

In a mixing bowl, combine the graham cracker crumbs, flour, sugar, and salt. Drizzle in the melted butter and mix until it resembles wet sand.

Set aside one-third of the crumb mixture. Firmly press the remaining crumbs into the bottom of the baking dish.

Using an electric mixer, beat the cream cheese until smooth. Gradually add sugar, then eggs one at a time. Fold in lemon zest, juice, and vanilla.

Pour the filling over the crust, smoothing it evenly. Sprinkle the reserved crumb mixture on top. Bake for 30-35 minutes.

Allow to cool to room temperature for about 1 hour before refrigerating for at least 3 hours.