Donuts: Whisk together flour, sugar, baking powder, and salt in a large mixing bowl.
In a small bowl, whisk together milk, egg, melted butter, and berries. Add to the dry ingredients and stir lightly till just moistened.
Pour batter into a freezer ziplock bag. Snip the corner and squeeze the batter into well greased donut pans. Bake at 425° for 8-9 minutes or till lightly browned.
Remove from pans. Cool and frost with strawberry cream cheese frosting.
Frosting: Beat cream cheese and melted butter till very smooth. Beat in berries, salt, and enough powdered sugar to get a spreadable consistency.