Preheat oven to 350°F/177°C and line two baking trays with parchment paper or silicone mats.
In a medium bowl, whisk together all of the dry ingredients: all-purpose flour, cornstarch, baking soda, and salt.
Using a hand mixer or stand mixer with the paddle attachment, cream the butter and sugar on medium speed until smooth, about 2 minutes.
Add egg and ube extract to the bowl. Mix, scraping bowl as needed, until mixture is combined and smooth.
Add all of the dry ingredients to the stand mixer and mix until dough is combined.
Use small cookie dough scoop to form dough into balls (about 1 ½ tablespoon each). Roll dough into granulated sugar, shape into ball, then place onto lined baking tray. This will be the bear's head.Take ¼ tsp of dough, roll into granulated sugar, shape into ball, and place on the upper left or right side of the head to make one of the ears. Repeat for the other ear. Place bears about 4 inches apart. They will spread while baking!
Bake for 8-10 minutes or until tops are set. They will not brown in the oven because of how purple they are.
Let cool on pan for about 5 minutes, then transfer to wire rack. Let cool completely.
To add the faces, use colored vegan royal icing (recipe in notes below) or melted vegan white and milk/dark chocolate. Place into small piping bags and cut a small tip. First, use the white to add the noses and ears, then the darker color for the eyes and nose.