In the bowl of a stand mixer fitted with the paddle attachement, add the sugars and lemon zest. Use your fingers to massage the lemon zest into the sugars for about 20 seconds. This helps to elevate the lemon flavor in the cookies once baked. 

Add the room temperature butter and mix on medium high speed until light and fluffy, about 3 minutes. Stop the mixer and use a spatula to scrape down the sides of the bowl.

Add the egg and vanilla and mix on low speed to combine well. Scrape down the sides of the bowl.

In a separate bowl, whisk together the flour, baking soda, cream of tartar and salt. Add the dry ingredients to the butter and egg mixture and mix on low speed until incorporated. Do not over mix. A few streaks of flour remaining is okay.

Remove the bowl from the mixer and use a large spatula to fold in the freeze dried blueberries, being careful not to over mix.

Chill the dough uncovered for 30 minutes. Once chilled, preheat the oven to 350°F. Pour the sanding sugar into a small bowl. Line two baking sheets with parchment paper. Use a medium cookie scoop to portion out the dough and roll each ball in the bowl of course sanding sugar, being sure to coat all sides. 

Place the cookie dough balls 2 to 3 inches apart on the prepared baking sheets. Bake in the center rack of the oven for 8 to 9 minutes or until the edges of the cookies are set and slightly golden brown. The center of the cookies will be slightly puffy.

Remove the cookie sheets from the oven and allow the cookies to cool on the rack for 5 to 10 minutes before transferring to a wire rack to cool completely. Sprinkle the tops with more course sanding sugar for extra crunch if desired.