Place butter in bowl of a stand mixer. Mix until soft and creamy.
1 cup butter (salted)
Mix in lemon zest.
2 Tablespoons lemon zest
Mix powdered sugar into butter one cup at a time.
1 pound powdered sugar
Mix in lemon juice 1 tablespoon at a time.
2-4 Tablespoons lemon juice
Notes
Keep leftover frosting covered in fridge for up to a week. Bring to room temperature and stir before using.If you need a firmer buttercream, you can use ½ butter and ½ Crisco. The flavor will change slightly, but your frosting will be a bit more stable.
Tips for making lemon buttercream frosting
Make certain your butter is at room temperature. I usually let mine sit out on the counter for at least one hour before I will use it.
Begin whipping your butter first, before adding other ingredients. This helps make certain your butter is nice and creamy.
If your powdered sugar is lumpy, sift it through a sieve before using. The lumps don't disappear when you add the powdered sugar to the butter.
Always add the lesser amount of recommended liquid. Sometimes you won't need to add any additional liquid or your buttercream will be too runny.
If buttercream is too thick, just add a bit more lemon juice.
If it's too runny, add a bit more powdered sugar.
This buttercream recipe does not hold up well in the heat. If it's too warm for a stick of butter to hold its shape, the buttercream won't hold its shape either.
Refrigerate buttercream as needed. Just let it come back to room temperature before using.
Use fresh squeezed lemon juice and don't skimp on the zest.