In a medium mixing bowl fitted with a paddle attachment, cream butter and sugar on medium speed for 2-3 minutes until pale and fluffy.
Mix in vanilla extract thoroughly.
Add salt and flour; mix until dough is fully incorporated, even if crumbly at first.
Crush freeze-dried strawberries and gently fold them into the dough, reserving some pieces for topping.
Roll dough to about ½ inch thickness on a parchment-lined surface and cut into shapes using a cookie cutter.
Place cookies close together on a parchment-lined baking sheet; refrigerate for 2 hours to chill the dough well.
Preheat oven to 325°F (163°C). Roll chilled cookies in extra granulated sugar before baking.
Bake cookies for 15-17 minutes until edges turn light brown. Cool completely on a rack.
Melt chocolate in the microwave in 30-second intervals, stirring until smooth and pourable.
Dip one side of each cooled cookie into melted chocolate and scrape off excess chocolate.
Sprinkle reserved strawberry powder or optional salt flakes on top of chocolate.
Place dipped cookies on a baking sheet and refrigerate for 10-15 minutes to set chocolate.
Enjoy your chocolate dipped strawberry shortbread cookies!