Cake



The promise of Cake is introduced by GLaDOS as an incentive for Chell to complete the test chambers in the original Portal.

Portal
The cake is spoken of frequently throughout Portal. It is often mentioned through dialogue.

Recipe
In addition to the simple mention of the Cake, an actual recipe is given. Additionally, the Intelligence Core will recite the recipe for the Cake.

Portal 2
The cake is referenced again in Portal 2, but much more infrequently. The earliest reference to it can be seen on computer monitors; it's recipe is displayed amidst gibberish. Another 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" (Chell would) fall for it]]. 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 the original Portal, Erik Wolpaw stated that it was removed because he and Valve were tired of the memes and had enough of cake jokes. However, in the third level of Portal 2, there is a rat man den that has a drawing of part of the cake.
 * 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.