Weighted Companion Cube CAKE!!




Introduction: Weighted Companion Cube CAKE!!

As the girlfriend of a major computer/video game geek, and a fan of portal myself, I decided to make the dear boyfriend this weighted companion cube cake for his birthday.

Note: This cake can be made with very little experience with fondant. But, I couldn't find any other way to make it without fondant, so you gotta use fondant.

Think I've said fondant enough?


Step 1: Making the Base

I used 2 8-inch square cake pans, and betty crocker's yellow cake mix for this cake. Just cool them until they're completely room temperature ((any heat will melt the frosting))

Aqua's Frosting Recipe?
3 Cups powdered sugar
3 tablespoons of butter.
4-5 tablespoons of COLD milk.
Mix well, add more or less milk as need be!

Frost the top of both cakes, and layer them on top of each other. Pretty easy, right? I thought so too.

Then frost along the sides as well. All this frosting will help the fondant stay in place, as well as give it a more pleasant flavor.

It doesn't have to be perfect, as it wont be what is showing.

You can add colors and/or flavors to your frosting as well. For this cake I recommend pink, as it will probably save you a step or two later!

Be sure to save some of the frosting for later, you'll need it!

Step 2: Its Like Play-dough, But Better!

Add some black / Grey food coloring to about 1-1/4th pound of fondant, and knead until you get an even color all over. Be sure to use powdered sugar, or else you'll end up with a big sticky mess!!

Once you have it to the color you want, and its even all over, roll it out until its big enough to cover your cake all over, including the sides.

Step 3: Smooth...Smooth!!!

After you have it rolled out to a large enough square, roll it onto the rolling pin, this will make it easier to put on the cake without tearing it.

After rolling it over the cake, let it sit for a minute.

Then smooth it down over the cake, being careful not to squish it!!

get your hands wet, and use them to smooth down all of the wrinkles. This will give it a smoother finish. and will make it easier to attach your other parts.

After its all nice and smooth. use a VERY sharp knife ((anything duller than super-sharp will pull the fondant, and may tear it along the sides. You don't want that.)) to cut away the edges that remain along the bottom of the cake, you should end up looking something like mine.

Step 4: The Side-parts!

Take up some more of than fondant stuff, and work some more coloring into it ((less than the base, but still some, most fondant is blinding white before you add color.)) Make sure its an even color.

Roll it out. You want it thicker than the base fondant, but not too thick.

Cut out 4 corner pieces, and 4 side pieces.

Also, cut out a circle, the size the top of a standard drinking glass.

Step 5: Attaching Them

Wet down one side of the attachments, and put it down in its appropriate spot. Its not THAT hard to figure out which piece goes where and how, but still I have pictures.

I used milk, cause that is what I had on hand.

It turned out well for me.

If you accidentally tear the base (like I did), take a small amount of the piece you cut off earlier, wet one side of it, then carefully massage it into the base.

Step 6: Cutting Out the Dents

No companion cube would be complete without those pretty pink dents in each side.

So take some of the Frosting you have left from earlier, and mix it with red or neon pink food coloring to make the right color.

Put it in a sandwich baggie, and cut off the corner, and use that as a decorating tube, if you don't have one on hand.

Next, cut out a cross on the top, and small dents on each side. Then fill those dents with pink frosting.

Then place the circle you cut out earlier in the center!!

Step 7: Draw a Heart, and You're Done!

Just draw a heart, freehand, or use a stencil if you can't draw hearts...

And there you have it, a weighted companion cube cake!!

Which, btw, is a lie.

Feedback would be appreciated, as well as any ideas on how I can improve.

Be the First to Share


    • Frozen Treats Speed Challenge

      Frozen Treats Speed Challenge
    • Backyard Contest

      Backyard Contest
    • Exercise Speed Challenge

      Exercise Speed Challenge

    27 Discussions


    8 years ago on Introduction

    This was requested by my son, for his 15th Birthday. Thank-you so much for this instructable! (My first forage into making fondant was fairly successful)


    8 years ago on Step 7

    YOU ARE AWESOME!! Thank you so much for posting this. Will be baking for my husbands birthday in a week :)



    no one ever gets me because, bec-c-c-cause.........

    .....I'm different.


    9 years ago on Introduction

    1. Dosent look like a cube
    2. this is a insult to the companion cube, you killed it.
    3. Nice cake :D i want sum

    but seriosly, your moking its death, the cake is a lie


    9 years ago on Step 3

    Ive found that an easy way to cut fondant is with a rotary cutter (i.e. a pizza cutter)


    10 years ago on Introduction

    A good friend of mine and I decided to try making this cake for a birthdayparty we were invited to. We all got to know eachother at a university summerschool in game developing so I guess we all qualify as geeks.
    Anyway we were all very satisfied with how the cake turned out, so I just wanted to thank you for the instructable!
    In case anyone is wondering, we added some goo's from "World of Goo" to the cake, also made out of fondant, call it blasphemy!
    Btw. we used a recipe for making our own fondant, mainly based on marshmallows, it was great fun :P


    Reply 9 years ago on Introduction

    awesome idea with the goos, physics based games belong with other physics based games also world of goo and portal were both just amazing games

    Duct Tape Dude

    Hmmm.... putting the cube in the oven looks oddly familiar...*sob* no! never again! I will not burn my pal again!!!


    10 years ago on Introduction

    My roommate and I are both huge portal fans.  I think I'll make this for his birthday (with a little help from his wife).


    10 years ago on Introduction

    This was a triumph.
    I'm making a note here: HUGE SUCCESS.
    It's hard to overstate my satisfaction.

    Aperture Science:
    We do what we must because we can.
    For the good of all of us
    Except the ones who are dead.

    (Chorus 1)
    But there's no sense crying over every mistake
    You just keep on trying till you run out of cake
    And the science gets done and you make a neat gun
    For the people who are still alive.

    I'm not even angry.
    I'm being so sincere right now.
    Even though you broke my heart and killed me.
    And tore me to pieces.
    And threw every piece into a fire.
    As they burned it hurt because
    I was so happy for you.

    (Chorus 2)
    Now these points of data make a beautiful line
    And we're out of beta we're releasing on time.
    So I'm GLaD I got burned think of all the things we learned
    For the people who are still alive.

    Go ahead and leave me.
    I think I prefer to stay inside.
    Maybe you'll find someone else to help you.
    Maybe Black Mesa -
    Anyway, this cake is great:
    It's so delicious and moist.

    (Chorus 3)
    Look at me still talking when there's science to do.
    When I look out there it makes me GLaD I'm not you.
    I've experiments to run there is research to be done
    On the people who are still alive

    And believe me I am still alive.
    I'm doing science and I'm still alive.
    I feel FANTASTIC and I'm still alive.
    While you're dying I'll be still alive.
    And when you're dead I will be still alive.

    Still alive
    Still alive


    11 years ago on Introduction

    GlaDoS:the enrichment center would like to inform you that the weighted companion cube cannot speak...in the event that the weighted companion cube does speak the enrichment center strongly advises you disregard its advice


    11 years ago on Introduction

    Bleck Fondant. I Made a companion cube cake last year, 3 layers and the corners on the sides of the cube were made of cake. Took awhile to get them to stay, but frosting and toothpicks works.