In a food processor, puree freeze dried strawberries until they are a fine dust.
In a mixer beat butter and sugar together along with 1 tbsp of milk on high for 3-5 minutes or until light and fluffy.
Add in strawberry dust and 1 tbsp additional milk and beat. Add more milk if necessary to reach desired consistency.
Ice your cake as normal. Store uneaten/unused frosting in an airtight container in the refrigerator.
Notes
Vegan
Use dairy-free butter alternatives like earth balance sticks or butter flavored Crisco. Also replace the milk with almond milk or coconut milk for the best results.