Preheat oven to 350 degrees F. Gather cookie dough ingredients and make blueberry powder by blending freeze-dried blueberries in a spice grinder, blender, or food processor. Set powder aside while you make the dough.

In the bowl of a stand mixer fitted with paddle attachment or with a hand mixer, cream butter and sugars until fluffy before adding egg, vanilla, and lemon zest. Blend again until combined and fluffy. Add dry ingredients and mix until well combined and a dough forms.

Divide dough in half. Add blueberry powder to one half and mix well to fully combine. Portion both doughs out into 1 tablespoon balls. *see notes if you want to skip this step

Place two balls together, fold them over each other once or twice depending on how swirled you want them and then roll into a ball. Roll in sugar and place onto a parchment lined tray about 2 inches apart, flattening the tops very slightly. Bake in preheated oven for 8 minutes. Repeat until all dough balls have been baked.

Let cookies cool on tray for a few minutes before transferring to racks to cool completely before storing. Make sure you enjoy some while they're still warm!