Add the freeze-dried strawberries to a blender, spice grinder, or food processor and blitz them into a powder (some small chunks are okay). This should give you about 6 tbsp of strawberry powder. Set aside.
Add the butter and sugar to a stand mixer fitted with the paddle attachment. Beat on medium speed until smooth and creamy, about 3 minutes.
Add the vanilla extract and 3 tbsp of the strawberry powder to the bowl and mix again, scraping down the sides of the bowl if necessary.
Add the flour and mix again until combined and a firm dough forms. Try not to overmix.
Shape the dough into a ball, and roll it out on a floured surface to about ½ inch thick. Use your heart-shaped cookie cutter to cut out cookies, then place them on a parchment-lined baking sheet at least 1 inch apart.
Place the baking sheet with the cookies into the freezer for 15 minutes, and preheat the oven to 350℉. After 15 minutes in the freezer, bake the cookies in the preheated oven for 14-15 minutes, until just turning brown around the edges.
All the cookies to full cool, then make the glaze. Stir together the powdered sugar, milk, and remaining 3 tbsp of strawberry powder until smooth.
Once the cookies are cooled, dip them top side down into the glaze, then allow the excess to drip off before transferring them to a plate or cooling rack. Allow the cookies to set for at least 2 hours before transferring them to an airtight container for up to 2 days.