I have aging off, and I just manually age up my sims. I have a household with a few kids in it that I made so my main sims kids could have friends. Each time I go into that household to age up one of the kids, the birthday cake that was made for the first sim is always still there, so I just reuse that. I age the sim up, then they go into the the dresser to change their clothing, and then I go back to my main sim, so they don't have time to eat it.
I was planning to do this when I aged up my husband and wife sim, age them up at the same time, but some greedy guts went and took a slice as soon as the candles were blown out.