To Make the Crust:
Preheat oven to 350 degrees F. Line an 8-inch springform pan or cake pan with parchment.
In a food processor combine the graham crackers, butter, sugar and salt, until the mixture resembles cornmeal. Press the crumbs into the bottom of the pan, and bake for 10 to 15 minutes, or just until it starts to turn golden brown. Cool the crust completely, then freeze the crust.
To Make the Cheesecake Batter:
Cream together the cream cheese, sour cream, sugar, salt, eggs, vanilla, lemon juice and cornstarch, until very smooth, scraping down the bowl as needed. Divide the batter equally into 3 bowls. Add the raspberry preserves and a drop of red dye to one. Add the scraped vanilla bean to the next. Add the blueberry preserves and blue dye to the last bowl.
Pour the red layer over the frozen crust and return to the freezer for about 30 minutes, or until the batter is slightly firm to the touch. While this layer is chilling, place the other bowls of batter in the freezer to allow them to set as well.
Once the red layer feels thick, but not frozen solid, very carefully pour the white batter over the red. Do this very slowly, in small amounts, so that it doesn't break the surface of the red layer. Freeze the pan again for about 20 minutes. Check to make sure the blue batter isn't setting too firmly in the freezer; if it is, move it to the refrigerator.
Turn the oven temperature to 300 degrees F.
Add the blue layer in the same careful way. Place the pan on a baking sheet. Place in the oven, then pour hot water in the baking sheet, which will help the cake bake evenly. (If you are using the springform pan, you will need to cover the bottom of the springform pan with foil, to prevent any water from seeping in). Bake for 1 1/2 to 2 hours, or when it is set in the middle.
When the cake is set in the middle, remove from the oven and allow to cool to room temperature, then refrigerate for several hours.
Run a hot knife blade around the edge before removing the cake from the pan. If you are using a regular cake pan, you will need to heat the bottom quickly over the stove, then cover the top with plastic, invert onto a plate and finally transfer to the serving platter. Refrigerate the cake while you make the topping.
In a small bowl add the gelatin to the cold water, stir to combine and allow to bloom for several minutes. Once the water has absorbed all the gelatin, add it to the hot simple syrup. If you made the simple syrup ahead, heat it. Add the blueberry preserves and transfer to a clean bowl to cool.
Once the glaze has come to room temperature, it will thicken, but still be pourable.
Place the blueberries on top of the cake.
Pour the thickened glaze over the berries. It will run down the sides, which I think is quite pretty. Refrigerate until the glaze has set a bit. If you prefer clean sides, use a hot metal spatula to scrape the excess off the sides (this is very easy to do).
Use a hot blade to cut the cake to keep the stripes distinct, and enjoy!