Blend the strawberries in a blender or food processor until completely ground up. Put it in a bowl and set aside.
Mix the butter, vanilla, half the powdered sugar, and a pinch of salt in a medium bowl. Scrape the sides and add the remaining powdered sugar, blended strawberries, and the milk.
Continue mixing until completely combined and is the desired consistency.
Use with this sugar cookie skillet or frost some cupcakes.
Notes
You don't want to add all the powdered sugar all at once or the mixture will be all over your kitchen.
You can add more milk, depending on your desired consistency.
This batch is enough to frost 24 cupcakes.
Store in an air-tight container in the fridge for up to a week or freeze for a month.