Cream softened butter in stand mixer with whip attachment until smooth.
Blend in vanilla.
Add 1/2 the confectioners sugar & most of the milk - stir slowly until moist- then whip until well combined.
Add remaining confectioners sugar & milk.
Beat on med-high about 3-4 minutes scraping sides of the bowl occasionally.
Texture will become very smooth.
Use immediately or store in airtight container for up to 2 weeks in refrigerator or 3 months in freezer.