Homemade Cake ... You're Joking, Right?

Ella: Are we decorating the house for the January birthdays? (we are having the fam over for all the birthdays in Jan- just to clarify)
Me: No we aren't.
Ella: Oh ... where is the cake.
Me: Kali's bringing it.
Ella: Where did she get it from?
Me: She made it.
Ella: WHAT? WHAT? (said in a high pitched girls voice). Mom, you can't make birthday cake, you have to buy it. (In a like, DUH you moron kinda voice)
Me: No you can make birthday cake.
Ella: ( In a completely shocked and somewhat betrayed voice) Why have never made me a birthday cake?

I can do a lot of things, but apparently making a homemade birthday cake is not one of them.