In a medium bowl, beat together ½ cup softened butter, a pinch of fine sea salt, 1 teaspoon vanilla extract, and 1½ cups powdered sugar on medium speed until smooth and creamy, about 3–4 minutes.

Gradually mix in 2–4 tablespoons of freeze-dried raspberry powder and 2–3 tablespoons of whole milk, adjusting for desired consistency. Set the raspberry buttercream aside while you prepare the cookie dough.

Preheat your oven to 350°F (175°C) and line two large baking sheets with parchment paper.

In a stand mixer, blend 1 cup of softened unsalted butter with 1 cup granulated sugar, ½ cup powdered sugar, 1 teaspoon fine sea salt, 2 teaspoons vanilla extract, and the zest of 2 large lemons.

Beat together on medium speed for about 4–5 minutes until the mixture is light and fluffy.

Add in 1 large egg and continue mixing for an additional 2 minutes until fully incorporated.

Slowly add 3 cups of all-purpose flour and ½ teaspoon of baking soda to the cookie dough with the mixer on low speed. Mix until just combined.

Using a cookie scoop or measuring cup, portion out about 3 tablespoons of dough for each cookie and roll into balls, then flatten them gently.

Slide the baking sheets into the preheated oven and bake for approximately 12 minutes, or until the edges turn golden brown.

Once the cookies have cooled completely, frost them with approximately 1 tablespoon of the prepared raspberry buttercream.