Using a stand mixer fitted with the paddle attachment, cream together the softened butter and powdered sugar until light and fluffy.
Then add in the vanilla extract and mix until fully combined.
Mix in the flour, strawberry powder, and salt until just combined. The dough should come together into a soft but not sticky ball.
Divide in half and press the dough into discs. Wrap tightly in plastic wrap and refrigerate overnight (or a minimum of at least 2 hours).
Line 2 baking sheets with parchment paper and set aside.
On a lightly floured surface, roll out the dough to your desired thickness (I like between ¼ and ½ inch thick). Then cut out the cookies into your desired shapes.
For these heart shaped shortbread cookies, I used these heart cookie cutters. But you can use whatever cookie cutters you want! This recipe makes about 40 heart cookies in various sizes, but will make more or less depending on the cookie cutters you use.
Place the heart cookies 1-2 inches apart on your lined baking sheet. Place the baking sheet in the fridge or freezer for a minimum of 20 minutes before baking. This ensures the cookies keep their shape.
While the cookies are chilling, preheat your oven to 350°F.
Bake for 8-12 minutes or until the edges are set. Bake on the middle rack of the oven and rotate the pan halfway through baking for the best results.
Let the strawberry shortbread cookies cool on the baking sheet for 2-3 minutes, then remove and let them finish cooling on a cooling rack.
Glaze
To make the glaze, whisk together the powdered sugar, strawberry powder, and milk in a small bowl, until smooth. The glaze should be runny.
Dip the tops of the cooled strawberry cookies in the glaze and place back on the cooling rack. Then sprinkle with crushed freeze dried strawberries if desired. After about 20 minutes the glaze will harden.
Notes
You can store these cookies in an airtight container at room temperature for up to 5 days.