Begin by draining a can of chickpeas or garbanzo beans over a bowl or measuring cup. Reserve about ½ cup of the chickpea liquid – known as aquafaba.
Store the remaining drained chickpeas for another use.
Measure the remaining ingredients.
In a large mixing bowl, add the aquafaba along with the lemon juice or vinegar and mix until it becomes lightly frothy.
Add the powdered sugar. You can either add all of it at once or add it in increments, I recommend increments if you are not using a stand mixer.
Add vanilla and continue mixing until there are no lumps remaining in the icing.
Once smooth, continue to mix for 3-5 minutes.
If you need it to be thicker for things like gingerbread house "glue" or piping thicker designs, you can add more powdered sugar. If you want it to be thinner just mix in a little water.
Use immediately by placing in a piping bag or store in the fridge for later in an airtight container. The icing will harden if left out for too long.