Portal Cake Recipe
Contrary to popular opinion, the cake is not a lie. At least, not this one.

Because I lived in a dorm section affectionately referred to as "the gamers' suite", I inevitably hear of every new major game release, and bear witness to the excitement that follows shortly after completion of said games.

This time was no exception, with the release of The Orange Box from Valve, or specifically, the game Portal. After hearing the "Still Alive" endgame track more times than I care to recall, and having everyone go into hysterical fits of giggling at the mention of the word cake...

I finally gave in to the inanity (and no, that's not a typo).

My suitemates were ecstatic and gleefully obliged me, providing several in-game reference photos of aforementioned cake. This image is probably the best one, alongside someone else's early attempt to re-create the cake from the recipe mentioned in the game itself (I have no idea where it can be found, as I've never played Portal before). However, since some elements in the recipe seem less than savory (I mean, fish shaped ethyl benzene?) I decided to do my own thing; start from the reference and build up from there.

It's an experiment in the truest sense, really. I haven't done this before, so what you'll see is what I'll get as I tinker around.

That being said, feel free to join me as I attempt to bring this unusual culinary project to completion.

NOTE: The Weighted Companion Cube is NOT my creation, but the papercraft artist and the build plans for him can be found here: Companion Cube Papercraft

Step 1: The Conceptual Blueprint

Believe it or not, there's a method behind the madness of all this.

When attempting to pull of a re-creation of something, looks are everything, if not a major part of the appeal. As obvious as it seems, this means that the inside of the cake, if you're willing to disregard the in-game recipe, can be anything you want, as long as it has the correct shape and has a dry, solid surface. You could take cardboard, frost the panels, and top it with red ping-pong balls and balsa wood chips if you were determined.
Basically, the type of cake base used can be anything your little heart desires, whether it be chocolate, devil's food, yellow cake, or even red velvet.

Well, almost anything - I wouldn't recommend trying it with spongecake or angel food due to the delicate structure of the crumb. Just as long as it can hold itself up in layers and can take frosting on the surface without much damage.

The same principle applies when deciding what to put between the layers. It's recommended that you put something there, since it'll help the layers stay together and make the overall cake more stable.

It can be as simple as frosting-in-a-can or whipped cream, or as complex as chopped fruit and melted chocolate. Nothing too wet, though, you want the layers moist, but not soggy.

Now, even though you can't take as many liberties with the exterior, the ingredients aren't set in stone for it either. Based on the reference photos, these main things make this cake recognizable (at least, to people who have played the game before):

a rough-looking, brown exterior
eight (8) cherry red decorations set in a ring of white frosting
said decorations evenly arranged in a circle on top
a thin white candle (optional) set in the center

The possibilities for replicating these components of the appearance are entirely up to you. See what works or is most readily available to you.

Step 2: Components

Myself, I'll be going for the simplistic approach, so my list of ingredients won't be very specific.

Note: The quantities shown were used for the "prototype" cake (the hemisphere), so if you're using the method I'm using, DOUBLE the listed quantities.

Cake Base

generic chocolate cake mix
canola oil
eggs
water

(All quantities according to the box of cake mix.)

Filling and Frosting

1/2 pint whipped cream (heavy whipping cream)

Exterior

4 oz. semi-sweet baking chocolate, shaved

Decorations

4 canned maraschino cherries, stems removed

Oh, and don't forget the basic kitchenware as well.

two (2) 9-inch circular cake pans
two stainless steel mixing bowls
measuring cups and spoons
spatula
fork (or a whisk, if you can get ahold of one)
small paring knife (or a larger one, to chop more chocolate faster)

Step 3: Cake Base

Follow the directions according to the cake recipe you'll be using, or the mix that you bought. If you're using a recipe, make sure it makes sufficient batter for the cake pans you're using.
Lightly oil the bottom of the pans to prevent sticking before adding the batter and placing in the oven.
Bake according to the recipe/mix and leave to cool.
Turn the cakes out of the pans onto a plate or a clean surface (like a silicone mat).

Step 4: Layer Construction

Since this is a prototype, I'll only be making a 1/2 cake (semi-circle) for this instructable using two 9-inch cake circles cut in half and stacked on top of each other.

You could leave the layers whole and just have a stack of two, but in my opinion, the cake looks too short compared to the reference when set up that way. If all goes well, I'll use 4 full layers next time.

Take the first layer and place the flat side down onto the surface carefully.
Prepare your choice of filling in another bowl.
Take a spatula, scoop a golf-ball size of filling, and plop onto the center of the top of the layer.
Spread the filling to a thickness so that it won't squeeze out under the weight of the other layers (too thick) or expose the cake underneath (too thin). Add more as you go, if needed.
Repeat for the areas between remaining layers.

Step 5: Exterior Construction

On to phase 2!

Prepare your choice of frosting (here, whipped cream).
Again, taking a golf-ball sized dollop of frosting, carefully spread it on top of the cake with a spatula.
Work slowly and add more as you need it, moving on to the sides after you finish the top.
If you're using whipped cream like I am, put the cake in freezer for about 5 min after the interior is completely coated as a safeguard against meltdown.
Don't worry about smoothing the surface, because the exterior of the cake in the game has a very rough surface. Convenient, no?
To match the color of the cake, you can add food coloring to a batch of white frosting, or in my case, add chocolate shavings to mimic the texture and tone of the surface (they'll stick to the whipped cream and completely cover any traces of white on the surface. The recipe in the game suggests using one can of "prepared coconut pecan frosting", if you can come by that.

I don't know if you can buy chocolate shavings, but in a pinch, small milk chocolate chips work too.

I went at squares of baking chocolate with a knife, but box graters work too.
Then I took the shavings and applied them to the coated surface of the cake with a spatula, making sure the board the cake was resting on aluminum foil to catch stray shavings. Press gently to minimize the white appearance of the cream.

Step 6: Finishing Touches

All that remains are the little details.

Drain the cherries and remove the stems. Cull the best looking undamaged ones for presentation.
Unfortunately, the only cherries I could manage to get ahold of were the ones you see in the photos, and a good bit smaller than I expected.
Strawberries can be substituted, too. Just wash, dry, and hull them by cutting off the tops with a paring knife.

From here, there are 2 ways you can go about it.

Step 7: The Simple Way

More steps, yes, but it takes less dexterity. Also useful for when time is short or you're not confident in the steadiness of your hands.

Take a bowl of white frosting (or whipped cream) and a spoon.
Take a scoop of frosting, this time half (1/2) the size of a golf ball.
Place it about 1/2 an inch from the edge of the cake. Try to make it an even, smooth circular dollop.
Repeat the previous 2 steps, only this time directly across from the first dollop.
Picture the top surface of the cake as a clock face, and the two previously created dollops at the 12 o'clock and 6 o'clock positions. Add 2 more dollops at the 3 o'clock and 9 o'clock positions.
Between the 4 existing dollops, add one more dollop in between each two adjacent ones, evenly spacing them out. You should end up with eight in all.
Take the red fruits and gently press one into each white dollop so the frosting/cream comes up the sides of it slightly.

Due to the size of the cherries, I ended up with 5 on this hemisphere of cake, but the general setup was the same.

Step 8: Not-as-Simple, But-Closer-to-the-Original-in-the-End Way

It's only two steps, but the piping takes skill (at least I have had trouble with it in the past).

Pour a small quantity of frosting (preferably white) or whipped cream into a plastic sandwich bag.
Cut off the corner tip and pipe a circle around the fruit.

You'll have to judge how much of the corner to cut off to form a proportionately sized white ring for the red fruits.

Or you could whip this little pastry bag up and use that.

Step 9: Candling

Acquire a small, thin smooth white candle.

Barring this, you can probably use any candle that'll fit on the cake and won't render it inedible.

Insert candle into the center of the cake.

Step 10: Admire and Enjoy

Serve promptly, or after a brief (1 hour) stint in the freezer, if you prefer your cake chilled.

I found that slicing the cake can prove challenging if you lack a large non-serrated kitchen knife. Even with the proper knife, the cake was so soft the slices started to fall off as soon as they'd been half cut-off.
So in retrospect, a good 6-8 hours in the freezer will probably firm it up a little for easier serving. Maybe not more than a day straight, though, if you don't want a frozen block of cake.

Your labors will most likely be truly appreciated by those who recognize the unique appearance of the cake and have played the game before. Giddiness, or in some cases, extended periods of laughter resulting from said recognition are not unusual, and to be expected.