Birthday cake

A Birthday Cake is an item that appears in The Sims 2 and The Sims 3. It is used to age up Sims to the next life stage.

The Sims 2
Birthday cakes are bought in Buy mode, where it is found in the Misc > Party section. It is used to age Sims (except young adults and elders) to the next life stage, but can only be used if the Sim is within 24 game hours of transitioning. Babies and toddlers can be aged up if a teen, adult, or elder carries them to the cake.

The Sims 3
"Usher in a new age with this white-hot pastry! Delicious, yet dangerous for the elderly and waistlines, the Birthday Inferno is a blazing flash of fun and excitement. (A Sim can throw a birthday party with this cake to transition to the next age category at any time.)"

The Birthday Inferno Birthday Cake is an object in The Sims 3 and can be bought at the supermarket. It can also be found in the Entertainment > Parties category in Buy mode, if Buy mode is set to "Sort by Function". It is used to age up a Sim by one life stage. It can be used to age up any Sim on the lot, not just Sims in the household. There's a 2% chance it will catch fire when Sims blow the candles.