Butter must be softened to room temperature for it to be able to form into a light & fluffy texture.
Beat the butter for 5 full minutes, until light and fluffy. Make sure you are scraping the bowl every couple of minutes to ensure everything is evenly combined.
Use your biggest bowl and largest sieve to sift the confectioner's sugar. This ensures no lumps are left in the powdered sugar.
Sift the Sugar
Add half of the sugar to butter. Mix on low until fully incorporated then increase to medium speed. Beat for 5 minutes
Add half of sugar
Scape the bowl down then add the remaining powdered sugar and mix for 3 more minutes.
Add the rest of sugar
Add the vanilla extract and heavy cream or milk and beat for another 3 minutes.
Add the liquids
Use however you'd like
Spread or pipe frosting. Store in the fridge for up to 7 days, let come to room temperature and mix before using.