Cream together the cream cheese, sour cream, sugar, salt, eggs, vanilla, lemon juice, and corn starch, until very smooth, scraping down the bowl as needed.
Divide the batter equally into 3 bowls. Add the raspberry preserves and 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, also place the other bowls of batter in the freezer to set them up 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 getting too set up in the freezer, if it is, move it to the refrigerator.
Preheat the oven to 300°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 about 1 1/2 to 2 hours, or until set in the middle.
When the cake is set in the middle, remove from 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 is set up 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.