32oz.powdered sugar (two 16 oz. bags or about 8 cups)
Leave the butter on the counter to soften a bit at room temperature. Or you can place two sticks of butter in the microwave and heat for 9-11 seconds to soften, then repeat with the other two sticks of butter. Once the butter is a little soft but is still firm then it is ready. You should be able to make an indent in the butter if you push firmly.
Place the butter in your mixing bowl and beat for a few minutes.
Open a bag of powdered sugar and add in about a third of the bag. Mix until combined. Continue until the whole bag is mixed in.
Add in the vanilla extract and mix until combined.
Open the second bag of powdered sugar and add in about a third of the bag. Mix until combined. Continue until the whole bag is mixed in.
Add in 3 tbsp of whole milk. Mix until combined.
Add in the last 3 tbsp of milk and mix until combined. If you need to adjust the consistency add in an additional tbsp of milk at a time.
Mix the frosting for about 2 minutes. Scrape the bowl, then mix for another minute.
Mix the frosting by hand with a spatula or spoonula for a few seconds to try to get out some of the air bubbles and make sure everything is incorporated.
Frost your cake, cupcakes, cookies, etc.!
Store any leftovers in an airtight container. It will last up to two weeks in the refrigerator, or you could freeze it for up to 3 months.