Make Crust: Place graham crackers in the bowl of a food processor and pulse until crumbs are formed. Add butter, brown sugar and salt and pulse to incorporate, until crumbs resemble wet sand. Coat an 8-inch square pan with cooking spray and pack crumbs firmly into the bottom of it. Refrigerate until ready to use.
Make the filling: In a large bowl, combine cream cheese, condensed milk and pasteurized egg product and beat on high with an electric mixer until smooth and creamy, about 2 minutes. Add lemon zest and juice and beat until fully incorporated, another 30 seconds. In a small bowl, combine the gelatin and boiling water and whisk until gelatin is entirely dissolved; let cool 2 to 3 minutes. Stir the gelatin into the cream cheese-lemon mixture until well incorporated. Pour the filling over the crust. Refrigerate for 8 hours or overnight, until filling is firm. Slice into 2-inch squares using a chilled knife coated with cooking spray.