Start by bringing the butter and eggs to room temperature—remove them from the refrigerator ahead of time.
To Prepare the Freeze-Dried Strawberry Powder: Place the freeze-dried strawberries in a high-speed blender or spice grinder and blend until they form a fine powder. Combine this powder with the granulated sugar and mix thoroughly. Store the mixture in an airtight container in a cool, dry place until ready to use.
To Make the Sparkling Strawberry Sugar: Stir together freeze-dried strawberry powder and sparkling sugar, using a ratio of 2 tablespoons of strawberry powder for every ½ cup of sanding sugar. Store this mixture in an airtight container in a cool, dry location until needed.
Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper. Set aside.
To Make the Cookie Dough: In the bowl of a stand mixer, cream together the softened butter and granulated sugar on medium speed until the mixture becomes light and fluffy—this should take about 3 minutes. Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract, strawberry extract, and red gel food coloring, blending until the mixture is smooth and evenly colored.
In a separate medium bowl, whisk together the all-purpose flour, cornstarch, baking powder, baking soda, cream of tartar, salt, and strawberry powder until thoroughly combined. Gradually add the dry ingredients to the wet mixture and blend on low speed just until the dough comes together—be careful not to overmix to ensure your cookies stay soft and tender.
Cover and chill the cookie dough in the refrigerator for at least 2 hours, or up to overnight.
Place the prepared Sparkling Strawberry Sugar in a small bowl. Using a medium cookie scoop, portion out 30 evenly sized dough balls. Roll each ball between your palms until smooth, then roll them in the sparkling strawberry sugar until they are completely coated. Arrange the coated cookie dough balls on the prepared baking sheets, spacing them about 2 inches apart.
Bake in the preheated oven for approximately 10 minutes, or until the tops of the cookies are just beginning to set. Remove the pans from the oven and let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.
Store the cooled cookies in an airtight container at room temperature for up to 3 days, or refrigerate for up to 1 week.