The cake is a lie.

No, not really. This one's actually very real and very delicious.

This Instructable will show you not only how to make a cake, but how to make THE cake from Portal.

The basic cake recipe for the middle layer can be used to make any homemade cake. If you want white cake, simply leave out the cocoa.

It's easy to do and relatively cheap. So let's get started!

Step 1: #1 Ingredients

The first step for this cake, like any cake, is to get your ingredients together. This particular cake can probably be described as a German Chocolate cake. It has two layers made from a box, and a center layer made from scratch (which is an important to this Instructable and cake). All of these ingredients were actually taken from a recipe appearing in the game Portal. http://www.planetfortress.com/dfa/portal-recipe.html
While it doesn't give the specifics of how to prepare it, with a little fooling around, I figured out the basics.

Pre-Packaged Chocolate Cake
1 (18.25 oz) package chocolate cake mix
3/4 cups vegetable oil
4 large eggs
1 cup semi-sweet chocolate chips

Scratch Chocolate Cake
3/4 cup butter or margarine, softened
2/3 cups granulated sugar
3 large eggs
1 teaspoon vanilla extract
2 cups all purpose flour
2/3 cups cocoa
1/4 teaspoon baking soda
1 teaspoon salt
1/4 teaspoon baking powder
3/4 cups water

Decoration
1 can vanilla frosting
2 cans coconut pecan frosting
1 small Cool Whip
1 small jar marachino cherries

Step 2: Making the Pre-made Cakes

To start off with, get all your ingredients for the box cakes out and ready. It's much easier to work if you don't have to run to the fridge and get something every 2 minutes.

You're also going to want two (2) 8-9 inch cake pans.

An important note! Get a cake mix that requires oil and eggs!

Now, follow the instructions on the cake box pretty much exactly. If the box instructions call for greased pans, do it. Also, preheat the oven according to the box.

Use the amounts listed in the ingredients I provided, such as 3/4 oil and 4 eggs. If the mixture is too thick, use a little water. You should probably be pretty good with just the liquid from the oil and eggs though. The other important step is to mix in the chocolate chips BEFORE you pour the mixture into the pans. I've forgotten this before, and let's just say it's not good.

Now, once you've poured the mixture into the pans, bake it! It's usually a good time now to take the butter for the next cake out and let it start softening. You'll know they're done when you insert a toothpick into the cake, and it comes out clean (meaning no goo or liquidy batter). Don't overbake them though! The residule heat from the pans will cook it a bit as it cools. Once they are done, take them out and put on some cooling racks to chill for a bit.

Step 3: Making the Scratch Cake

Now, while the other cakes are cooling, you can start making your very own, homemade cake!

Again, remember to get all your ingredients out before hand.

Preheat the oven to 350 F (or 176 C for you metric people).

In a medium/large bowl, "cream" together the sugar and butter. Creaming them means to beat them together with an electric beater till they're creamy and white in apperance. Beat in the eggs, one at a time. Next, stir/beat in the vanilla. In a seperate dry bowl, combine the flour, baking powder, salt, and cocoa and mix together until uniform throughout.

Now I mentioned the baking soda before and you're probably like "Brian, when do I use that?" Well, in the Portal recipe, it included both baking powder and soda. The recipe I found online to make a homemade cake only included baking powder. I've made this cake twice using baking powder, but never with baking soda. If you want to be adventurous and try it, be my guest and mix it in with the dry ingredients. If it comes out fine, post in the comments and I'll change the recipe. Just because I never did it doesn't mean you shouldn't ;)

Now, combine the dry mix with the creamed mixture and mix well. It should be pretty thick, so don't expect much. Now, add water until the batter is pretty smooth and pourable. You don't want it to be so thick it stalls your beater (it's happened), but you don't want it to be super runny either. With some practice, you'll find the water sweet spot ;) I find it to be around 3/4 cup to 1 1/4 cups.

Now, your other cakes should be done, so carefully remove one of them from its pan. Wash the pan real quick with some soap and water and dry. If you have a 3rd cake pan seperate from the other two, ignore that last part. Grease and flour your cake pan and pour in your batter.

Bake your cake for 30-40 minutes. I usually find that it takes a little longer. Remember the toothpick test! Last time I made this, I was in too much of a rush, removed it too soon, and when I went to cut it, the inside was still batter.

Once done, allow to cool. This could take a while, so go watch some TV or play a game for a bit (might I suggest Portal?).

Step 4: Decorating the Cake

Now that your cakes are cool and Portal is sufficently beaten, find yourself a nice plate or casserole dish with a good sized depth. It should be as big around on bottom as your cake is, as you're going to be putting it on there to decorate it. Flip the dish over and put your first pre-made cake on there (doesn't matter which). Find a nice, big knife (a bread knife is perfect) and try to cut straight across the top of the cake to make it level. This takes a little trying, and I am by no means a pro a this. Just try to get it level as possible. Once it's cut, crack open the vanilla frosting and spread a nice, thickish layer on top.

Place the scratch cake on top, rinse and repeat. On the final pre-made layer, don't put the vanilla frosting on top.

Now, if you have a frosting spreading type knife, now would be the time to use it. Scoop a good amount of coconut pecan frosting on top of the cake and spread it around the top and sides. Do until the cake is sufficiently coated in frosting. If the frosting starts to droop or fall off, put the cake in the fridge or freezer to chill and firm up for a bit.

Wait to put the whip cream and cherries on until right before serving. Take a Ziploc bag (small works fine) and put some Cool Whip in it. Clip the corner of the bag to make a cheapo pastry bag. Squeeze out whip cream dolops around the cake. Get as many cherries out as you have whip cream spots. Give them a little rinse, dry, and place on top of whip cream.

Step 5: Enjoy!

The cake should look fantastic and delicious. Add a candle and "Still Alive", and you're set for a Portal evening!

I should warn you though, the cake is incredibly rich. It took me an hour just to finish one piece. Seriously, share it with your friends. :)