Beat butter until light and fluffy, at least 2 minutes.
Add powdered sugar, vanilla, salt and a Tablespoon or two of milk or cream. Add more milk or cream as necessary to get a nice smooth frosting. Beat at least 3 more minutes.
Process the freeze dried strawberries in a blender or food processor until they are a fine powder.
Mix the strawberry powder into the frosting. Adjust the final texture with a little more powdered sugar or milk as necessary.