Preheat oven to 325°F and adjust rack to the middle position. Line an 8-inch square pan with a foil sling and grease the foil.

Process graham crackers into fine crumbs. Add melted butter, sugar, flour, and salt; pulse to combine.

Press mixture into pan and bake until lightly browned and fragrant, 12–15 minutes, rotating halfway. Cool completely.

In a stand mixer, beat cream cheese until smooth. Gradually add sugar and mix until incorporated.

Beat in eggs one at a time. Add sour cream, lemon juice, and vanilla; mix just until blended.

Pour filling over cooled crust and spread evenly. Bake 35–40 minutes, until edges are set and center slightly jiggles.

Cool on a wire rack for 2 hours, then refrigerate at least 3 hours or overnight.

Lift out using foil, cut into 16 bars, and serve. (Freeze uncut bars for up to 1 month; thaw at room temp for 4 hours.)