I'm Rachel, A.K.A. The Nintendette, an avid Nintendo fan, journalism & creative writing student, & overall video game enthusiast. Check here every day to see daily easter eggs, game reviews, & other video game goodies.
Apparently, the cake isn't a lie—the recipe is right in the game! The recipe can be found fragmented and displayed alongside binary code on the computer monitors in the office levels of the original Portal game.
The recipe calls for:
1 (18.25-ounce) package chocolate cake mix
1 can prepared coconut–pecan frosting
3/4 cup vegetable oil
4 large eggs
1 cup semi-sweet chocolate chips
3/4 cup butter or margarine
1 2/3 cup granulated sugar
2 cups all-purpose flour
GLaDOS also recommends that you decorate your cake with various garnishes including: Fish-shaped crackers, fish-shaped candies, fish-shaped solid waste, fish-shaped dirt, fish-shaped ethylbenzene, pull-and-peel licorice, fish-shaped volatile organic compounds and sediment-shaped sediment, candy-coated peanut butter pieces (shaped like fish), alpha resins, unsaturated polyester resin, fiberglass surface resins and volatile malted milk impoundments, an entry called: "How to Kill Someone with Your Bare Hands", 3 tbsp. rhubarb on fire, adjustable aluminum head positioner, slaughter electric needle injector, and cranial caps. Apparently the cake also contains preservatives, including gas and odor control chemicals that will "deodorize and preserve putrid tissue". Yum.
In reality, however, the cake is based off of one from a bakery called The Regent Bakery and Café not too far from Valve's headquarters in Redmond, Washington. Man, now I really want some cake.