Blueberry Frosted Lemon Cookies

Preheat the oven to 350℉ (177℃). Line baking sheet pans with silicone baking mats or parchment paper.
In a medium mixing bowl, whisk together the cake flour, cornstarch, baking powder, and salt. Set aside.
In a small bowl, combine and massage the granulated sugar and lemon zest to release the natural lemon oils. This enhances the lemon flavor in the cookies. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment or in a large mixing bowl with an electric hand mixer, cream the unsalted butter, vegetable oil, powdered sugar, and lemon-infused granulated sugar until smooth and creamy. Add in the egg and lemon juice and mix until smooth. Pour in the dry ingredients and mix on low speed until a soft cookie dough forms.
Portion the cookie dough using a large cookie scoop (3 tablespoons) and place on the prepared baking sheet pan, allowing room for spreading. Bake the cookies for approximately 12 minutes until the cookies puff up in the center and remain pale on the edges. Cool the cookies on the pan for 1 minute and then transfer to a wire rack to cool completely.

In the bowl of a stand mixer fitted with a paddle attachment or in a large bowl with an electric hand mixer, cream the unsalted butter for 5 minutes until light and creamy.
Add half of the powdered sugar and mix on the lowest speed setting until fully combined. Add the remaining powdered sugar and continue to mix on low until fully incorporated.
Use a food processor to grind the freeze-dried blueberries into a fine powder. Then, add in the freeze-dried blueberry powder to the butter mixture and mix on low speed until well incorporated.
Add the heavy cream, vanilla extract, and salt and mix on low speed until combined. Scrape the bottom and sides of the bowl occasionally to ensure the frosting is well mixed.
Increase the speed on the mixer to medium and whip the buttercream for about 2 to 3 minutes until it is smooth and creamy. Turn the mixer to low speed and mix the buttercream for several minutes to remove any air bubbles.

Fill a piping bag fitted with a Wilton 1A piping tip with the blueberry frosting. Pipe a swirl of the frosting onto the cookies and spread the frosting with an offset spatula. Decorate the cookies with finely chopped freeze-dried blueberries and lemon zest.

Storing & Serving:

Room temperature: Store the cookies in an airtight container at room temperature for 1 to 2 days.
Refrigerator: Store the cookies in an airtight container in the refrigerator for 2 to 3 days. Serve at room temperature for the best taste and texture.
Freezer: Store the frosted cookies in an airtight container in the freezer for up to 3 months.

Note: Metric conversions and nutritional information are calculated automatically. I cannot guarantee the accuracy of this information.