The company launched a Salted Caramel Spice cake "just in time for 'Spice-tember,'" they said in a press released.
The new flavor became available on Tuesday, Aug. 27, and is joining the menu for a limited time as a seasonal treat. It tastes like butter and a mix of different fall spices.
There's also a matching cake shake, and for the month of September customers can get a $1 slice of the new cake with the purchase of any entrée.
Portillo's classic flavors - chocolate cake, strawberry shortcake, and chocolate éclair cake - are available year-round.