In a stand mixer, combine the granulated sugar, brown sugar, and freshly grated lemon zest. Massage the zest into the sugars until fragrant, about 1-2 minutes.

Add the room temperature unsalted butter to the sugar mixture. Mix on high speed for about 3 minutes, until the mixture is light and fluffy.

Crack in the egg and add the vanilla extract, mixing until everything is well blended. Scrape down the bowl as needed.

In a separate bowl, whisk together the flour, baking soda, cream of tartar, and salt. Gradually add this to the wet ingredients, mixing until just combined.

Gently fold in the freeze-dried blueberries using a spatula.

Cover the bowl with plastic wrap and chill the cookie dough in the refrigerator for 30 minutes.

Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper. Portion the chilled dough and roll each ball in coarse sanding sugar.

Bake for 8-9 minutes, or until the edges are lightly golden while the centers remain soft. Cool on a wire rack.