Puree strawberries in a blender or food processor.
Heat pureed strawberries in a saucepan until boiling. Stir often and allow strawberries to simmer for 15-20 minutes. Remove from heat and allow to cool completely.
In a stand mixer beat butter until light and fluffy.
Add 1 cup of powdered sugar to butter and mix well.
Mix in half of the pureed strawberries.
Add another cup of powdered sugar and remaining strawberries. Then add the remaining cup of powdered sugar and mix until well combined.
If you would like a thinner frosting add 1 tablespoon of milk.