In a medium microwave safe bowl, heat the 1 cup of frozen blueberries in 20 second increments, stirring after each time, until they are soft, liquidy and jammy. This took me about 2-2.5 minutes. Set aside to cool. They will thicken more as they cool.

In a large bowl, whisk together the 2 cups multipurpose gluten free flour, 1.5 tablespoons of cornstarch, the 1.5 teaspoons baking powder and the ½ teaspoon of kosher salt. Set aside.

In a small bowl, using a spoon, mix together the remaining 2 heaping tablespoons of cornstarch with the 3 tablespoons of water until thin and watery. It will be thick and tacky at first.

In a large bowl of an electric mixer fitted with the paddle attachment, beat the ½ cup unsalted butter or vegan baking stick and 1 ¼ cups of granulated sugar until soft and creamy. About 2-3 minutes.

Slowly beat the cornstarch water mixture, 2 tablespoons of milk, 3 tablespoons of the cooled jammy blueberries (you may have some left over) into the creamed butter and sugar. It will look magenta and chunky.

Slowly beat in the gluten free flour mixture a little at a time until just combined. The dough will be super sticky and lavender. Keep the dough in the bowl, cover the top with plastic wrap and refrigerate for at least 2.5 hours. You must not skip this step or the cookies will spread everywhere. If you chill the dough overnight but it will turn blue instead of lavender with blue flecks.

After 2.5 hours, preheat the oven to 325 degrees Fahrenheit. Line a baking sheet with parchment paper. Set aside.

After the 2.5 hours, using a large cookie scoop, make 12 scoops with the dough. (I use a 2 ounce cookie scoop).If the dough is sticking to the cookie scoop, wash the scoop half way through to get off any stuck on dough.Roll each dough ball in the extra 2 tablespoons of granulated sugar to coat completely.

Place dough balls about 3-4 inches apart on the parchment lined baking sheet. Bake the cookies at 325 degrees Fahrenheit for 15 minutes. Store extra dough balls in the fridge while the rest are baking if they don't all fit. I only bake 6 at a time.

Immediately reshape the cookies when they come out of the oven by using a spatula to push them into a circle shape and let cool on the baking sheet for 5 min before transferring to a cooling rack. If you don't do this, the cookies will break apart into a giant mess.Repeat this with the remaining dough balls.