Cake



The promise of Cake is introduced by GLaDOS as an incentive for Chell to complete the test chambers in the original Portal. It is referenced in many of the Rattmann's dens as a lie, sparking the "The Cake is a lie".

Portal
The cake is spoken of frequently throughout Portal. It is often mentioned through dialogue as well as Rattmann's wall art in his dens. Although the dens frequently claim that the cake is in fact a lie, the ending of Portal shows the actual cake. There are rumors still though on how exactly the cake was introduced to the game. There are comics, short films and basic quotes that show different points of the rumor. Some say that Chell asked for it as one of the rewards for completing the test chambers, while others say that GLaDOS gives it as a primary "Prize" for test subjects.

Recipe
In addition to the simple mention of the Cake, an actual recipe is given. The recipe can be found on several computer screens after Chell's escape from death. Additionally, during the battle with GLaDOS, the Intelligence Core will recite the recipe for the Cake. The recipe often contains inedible or undesireable ingredients, such as "fish shaped ethyl benzene" or "cranial caps."

Portal 2
The cake does not make any appearances in Portal 2, though is referenced once through a sticker on the fake door before GLaDOS takes Chell to her chamber, mentioning that she [[Media:GLaDOS fgbrvtrap02.wav|"...honestly, TRULY didn't think you'd fall for that."]] This contradicts the common notion that GLaDOS may have forgotten about the cake after the destruction of the Intelligence Core.

Trivia

 * The cake does not appear in Portal 2 as it did in Portal 1, Eric Wolpaw stated that it was removed because he and Valve were tired of the memes and had had enough of cake jokes.
 * The cake slice icon shown on the neon panels throughout Test Chambers in Portal appears in another Valve game, Alien Swarm, as the icon of the achievement "Perfect".
 * The icon has also appeared on the TF Birthday Noise Maker item's icon in Team Fortress 2, with the cherry removed.
 * The cake was put in the game as inspired from the Black Forest cake sold in a bakery near the Valve headquarters.