Licking the spoon.
On Christmas Eve Zoe and I baked brownies for Christmas dessert, and I told her how when I was a little girl we used to make brownies with Grammy.
Uncle Jim and I would take turns putting in ingredients and stirring the mix until it was ready for Grammy to pour into the pan for baking. And then... when it was all done... Uncle Jim and I used to fight over who got to lick the spoon and how Grammy made sure we both had a spoon to lick. Zoe just gave me this look of complete lack of understanding... and said "Why Mommy, why did you fight with Uncle Jim?"
I think she understands now.