Place the Shortbread cookies in the blender, and blend them until they're fine crumbs. Pour the Shortbread crumbs into a bowl, and add 1 Tablespoon of sugar, and stir. Add the melted butter, and stir well, coating all the shortbread crumbs in the butter.
Place parchment paper in the bottom of each muffin space in the muffin tin, leaving strips that come up the sides of the muffin space (see photos). Place 2 Tablespoons of crust in the bottom of each muffin space, on top of the parchment paper, and press evenly into the muffin tin with fingers. Place the muffin tin into the freezer.
In the mixing bowl of a stand mixer, place the softened cream cheese, and blend until smooth. Scrape down the sides of the mixing bowl, and blend again. Add the heavy cream, and blend. Scrape the bowl again, and blend until smooth. Add the vanilla, and granulated sugar, and blend. Add the 2 cups of powdered sugar a little at a time, blending between additions, until all the powdered sugar has been added. Scrape down the sides of the bowl again, and blend one more time on high speed to make sure the cheesecake mixture is smooth and creamy.
Divide the cheesecake mixture into thirds, leaving 1/3 of the mixture in the mixing bowl, and two other bowls with 1/3 of the mixture in each bowl. Place one of the bowls in the refrigerator. In the other bowl, add 5 or 6 Blackberries, and mash them into the cheesecake mixture. This will give you a light reddish purple color. Stir well to completely blend the color into the plain cheesecake. Add a small amount of the purple food coloring gel to the mixture, and stir. You should have a light or pastel color in the bowl. Place the light purple bowl in the refrigerator.
In the mixing bowl, add about 10 Blackberries to the mixture, and blend on medium speed, which will give a reddish purple color to the mixture. Add about a teaspoon of the purple food coloring gel to the mixing bowl, and blend well. You should have a color similar to the dark color in the photo's shown. If your color is not dark enough, just add a little more purple food coloring until the desired shade of purple is reached. Remove the muffin tin from the freezer, and add about 2 Tablespoons of the dark purple color cheesecake to the muffin tin on top of the shortbread crust. Even the cheesecake mixture in the tin with the back of a spoon. Place the muffin tin back in the freezer for about 1 hour.
After an hour, check the cheesecake - it should be frozen to the touch ; if it's not, place it back in the freezer for another hour. Remove the light purple color cheesecake from the refrigerator, and place an equal amount in the muffin tin, on top of the dark color cheesecake. Place the tin back in the freezer for about 2 hours. Remove the muffin tin from the freezer, and check to make sure the cheesecake is frozen to the touch. Remove the plain, or white layer of cheesecake from the refrigerator, and fill the muffin tin with the cheesecake. Place the muffin tin back in the freezer, and leave overnight for best results.
When ready to serve, slide the thin metal frosting spatula between the parchment paper strip and the tin, and carefully lift out the cheesecakes. Place on dessert plates, top with whipped cream, and Blackberries and serve immediately. Enjoy!