Cupcake iPhone and iPad apps?  You bet there are...

Cupcake!

The original and still best cupcake app on the iPhone & iPod Touch. Bake, decorate, and eat virtual cupcakes with all kinds of flavors & toppings! Make infinite numbers of cupcakes with NO additional in-app purchases for coins or tokens.

Link: Cupcake!

iCupcake

Build your own cupcakes and send them to your friends. Choose from various cakes, icings, toppings, and candles. Press the candle to light it.

Link: iCupcake