In a stand mixer fitted with the paddle attachment, mix the softened butter on medium-high speed until smooth, about 30 seconds. Scrape down the sides of the bowl.

Add the powdered sugar, 2 tablespoons of milk, and vanilla extract. Mix on the lowest speed until combined, then mix on medium-high speed until fluffy, about 2 minutes. Scrape down the bowl halfway through mixing. Add 1 tablespoon of milk, and mix until smooth and fluffy, 15 to 30 seconds.

For a Thinner Frosting: Add an additional 1 teaspoon of milk, mix on medium-high speed for 15 seconds. Add more milk until the desired consistency is reached.

For a Thicker Frosting: Add in 1 tablespoon of powdered sugar, mix on medium-high speed until smooth, about 15 seconds. Add more powdered sugar until the desired consistency is reached.

Use the frosting as is, or add gel coloring or food coloring and mix until combined. Use immediately or cover with plastic wrap. Refrigerate if not using right away.