Dissolve salt in milk: stir salt into milk for 20-30 seconds so it starts to dissolve.
Beat butter and vanilla: beat butter and vanilla extract with a stand or hand mixer for 1 minute on medium speed until smooth.
Add sugar in four batches: add a quarter of the sifted powdered sugar to the butter and mix briefly on low to incorporate, then beat on medium-high speed for 1-2 minutes until light and fluffy. Repeat that process with the three remaining batches of powdered sugar until all sugar has been added and frosting is very light and fluffy, and has significantly increased in volume.
Add in milk: add in milk/salt mixture (be sure to scrape in the salt from the bottom of the container), and beat on medium-high for 2 minutes until liquid is fully incorporated and frosting is fluffy again.
Frost, share and enjoy: frost one 8" or 9" round two-layer cake, two 9” x 13” sheet cakes, or 36-48 cupcakes, then share the sweetness and enjoy! (or grab a spoon a give it a try right out of the bowl - no judgement here *wink*wink)
Test Kitchen Tips
Make sure your butter is properly soft for this recipe as you'll need soft, creamy butter to properly whip it into a light and fluffy buttercream. I also recommend using a higher quality butter as the flavor is really going to come through in this recipe.
A 1X batch of this frosting makes about 4 ½ cups when whipped to full volume which is enough to frost one two-layer 8" or 9" round cake, two 9" x 13" sheet cakes, or 36-48 full-sized cupcakes depending on how generous you are with your frosting.
This recipe has a decent amount of salt to balance out the sweetness (which I prefer), but if you're not used to using a lot of salt in your cooking or baking, feel free to use a scant ¼ teaspoon or leave it our altogether. It won't alter the texture, it'll just give you a more noticeably sweet frosting.
This recipe is super light and fluffy which means you will see bubbles, but if you'd like to smooth it out a bit for frosting a cake, allow it to mix on low speed for 2-3 minutes when you finish whipping it to get rid of some bubbles. You also can use a spatula to work the frosting back and forth against the side of the bowl to smooth it out and remove some bubbles as well.
⭐ Did you try this tasty recipe? ⭐Please give it a ⭐ rating in the recipe card or leave a comment at the bottom of the page to help others find this sweet recipe. I’d love it if you'd share your treats (literally and electronically!), and tag @mint.and.mallow.kitchen on Instagram or Facebook so I can see your beautiful bakes! Xo, Jocelyn