1. Preheat oven to 350°. Cut butter into 1/2 inch cubes. In a food processor, add cubed butter, flour, brown sugar, and salt.
2. Process until mixture forms small lumps.
3. Sprinkle into a greased 13 x 9 x 2 inch baking pan, pressing down with spatula to form crust.
4. Bake in the middle of oven until golden brown, about 20 minutes.
5. In a bowl whisk cream cheese until smooth then add eggs, white sugar and vanilla.
6. Evenly spread preserves over hot shortbread for traditional look then cover with cheesecake mixture. For a more stable bar, mix preserves into batter.
7. Bake for 20 minutes. Cool completely, then refrigerate at least 3 hours ( good luck with that step).