Line a 9-inch square baking pan with plastic wrap, letting excess extend over sides of pan.
In a medium bowl, combine graham cracker crumbs, brown sugar, and salt. Add melted butter and vanilla, stirring until moistened. Using a measuring cup, press mixture into bottom of prepared pan. Freeze while preparing fi lling.
Place ¼ cup (57 grams) water in a small saucepan. Sprinkle gelatin over water, and let stand for 10 minutes. Heat over low heat, stirring constantly, until gelatin is dissolved. Set aside.
In the container of a blender, place cream cheese, condensed milk, and lemon zest and juice; blend until combined and smooth. Add blueberries, and blend until uniform in color. (Some blueberry bits will remain.) With blender running, add warm gelatin mixture, blending until well combined. Pour filling over prepared crust. Smooth filling over crust.
Place Lemon Curd in a plastic piping bag, and cut off tip. Pipe Lemon Curd in thin lines over fi lling. Using a wooden pick, swirl Lemon Curd. Refrigerate for at least 4 hours or overnight. Using excess plastic as handles, remove cheesecake from pan, and cut into bars.