I am making a cake for my brother's birthday which is an iPhone with a depicition of a computer game he's writing and will soon launch on the screen.

I didn't want to just decorate on top of a cake to do this, I've decided to go a step further (and make my task harder in the process!) I am planning to make a chocolate orange cake with a black chocolate ganache (and foil covered card strip) for the outer shell of the phone.

For the screen I am planning to make the game imagery using coloured fondant icing. I was hoping to put this in a fondant lined rectangular cutout where the screen will be and then flood this with uncoloured orange flavour jelly, to simulate the glass screen. I also have a sealed light tube which I'll tuck into a fold at the top and wire into the cake to make the screen illuminate - which should carry brilliantly through the jelly.

My question is this: will the colouring on the fondant pieces run or bleed into the jelly solution? I have colouring to mix into the fondant and also colouring pens to draw directly on the outside.

If it is going to run... is there any way to protect it? I thought maybe a sugar syrup or shortening glaze on the fondant to seal it from the jelly... does anyone have any ideas or thoughts on this?

The jelly solution can be well cooled when it goes on so the heat shouldn't be an issue. I'm attempting all of this over the weekend so any help would be much appreciated!

yes, it will bleed. the gelatin even after is set is cold, very cold and it reacts to the fondant and bleeds and bleeds. use isomalt.

patty*

There are two things you can do to minimize the bleeding. One is to keep the coloring to a minimum, that is to use the least amount of coloring you can to get a shade reasonably close to the one you want. The other is to pour the gelatin mixture over the fondant designs as close as possible to the time you'll be serving the cake. If you use a gelatin with a high enough bloom, it should harden in short order in the quantities you'll be using for the phone. The less time the fondant spends in the gelatin, the less chance the vegetable dye has to bleed. Isomalt is, in my experience, difficult to use (this could just be me and my lack of experience, of course), but if your piping skills are okay, maybe royal icing would be a good substitute for fondant, supposing that fondant leads to more bleeding just because it's fondant. Hope this helps!

Could you use modeling chocolate? Maybe wouldn't bleed?

Hi, thanks for all of your suggestions.

The isomalt is a no go as there's nowhere within about 30 miles of me that would sell it - we have very limited craft/cake shop facilities around here alas.

This does need quite a bit of colour unfortunately - being a video game I'm recreating it is all about the bright colours.

Modelling chocolate - again, impossible to buy around here. I did see a guide for mixing corn syrup into melted chocolate and letting it cool to make your own. I might give that a try... but corn syrup is a very American thing, we don't seem to get it over here. The closest thing I guess is golden syrup (or glycerin) which is made from sugar beet not corn starch with enzymes added. I guess I'll have to have a play!

Thanks for your suggestions.

One other thing, what does "high bloom" actually mean in reference to the gelatin?

Cheers and Merry Christmas!

What about making a sheet of gelatin that you can cut to shape after it's hardened, then placing it over the fondant.

Another thought is...leave the fondant area white. Get a sheet of translucent edible rice paper, draw the design on it with edible markers. Cut it to size, lay it face down on white fondant so the image shows through the back (make sure your image is reversed when you draw it). Place the cut-to-size gelatin sheet on it.

Not really sure these won't bleed either. But you could test it.

If all else fails, Since it's for your brother and you will be there at serving time, place a piece of plastic wrap between the colored fondant and the gelatin sheet. Then, when it's time to serve, take the cake into the kitchen, remove the gelatin, plastic wrap and lights before cutting.

Piping gel?

I would let my artwork set up as long as possible then pipe a thin layer over and smooth with a spatula.

Y'know--test it first on a scrap--the fondant colors shouldn't run but markers are iffy. They might react to the extra pressure of the spatula.

Homemade piping gel, at least mine comes out more yellow--store bought is clearer but still it's not perfectly clear so perhaps a tiny tiny touch of purple to clean it up. Like tint a tiny amount of piping gel with a tiny amount of purple. Then take a tiny spot of that and put it in your gel to de-yellow.

Pure brainstorm ideas--haven't tested anything like this in a while. Always always test first.

SimonP -

You can use glucose in place of the corn syrup. I've been told by others in UK that this is what they use to make it, and it is readily available there.

Theresa

I tried filling a fondant/gumpaste beaker with jello once and it was a disaster. The moisture from the jello just melted/dissolved the fondant. They don't play well together.

Thank you all so much for your advice, it has been really helpful indeed. After some experiments I have found that fondant basically does as was suggested and dissolves in the jelly. Modelling chocolate with colouring worked in to it does not seem to do much damage, especially if it is really really cold when the gelatin mix goes on. I think the trick would be to pour REALLY slowly to avoid washing around the pieces with the liquid and disturbing the pigment.

I'm not sure I'd manage to transfer in a sheet of set jelly without it breaking up... that sounds like it'd be a good option though. Can anyone think how I could get it on there? Obviously with fondant I'd drape it over as rolling pin and apply but I can't see that working with jelly!

Yes I would also suggest making it with less water than usual. Also, I think maybe trying to freeze the sheet of jelly would make it easier to work with and less likely to break. I would flip the jelly sheet when really cold/frozen onto a pliable mat like one of those flimsy chopping boards/placemats, and then flip it onto my cake carefully. Again, I have never done it but I agree that rolling on a rolling pin wouldn't work...

Sorry I couldn't get back to you till now. The bloom number of gelatin is a number that tells you how fast any given gelatin will set up and how hard it will be once it does. The higher the number the faster it will gel and the firmer it will be (using a standard amount of water, of course). The highest bloom I've been able to get is 286 and it's wonderful stuff! It just occurred to me that there is something else you can do: lay down a nice, firm layer of milk-based gelatin in the area where your figures will be (this won't be any good for backlighting, though, because this gelatin is opaque). Then draw your designs - reversed - with food-safe markers on a regular piece of paper. Once these designs are quite dry, place them exactly where you want them on the white gelatin, press them down a bit with your fingers and let them sit for a few minutes. When you lift them, the images will be quite bright. I've done a few of these on larger gelatins and they're very crisp and colorful. The colors will spread a little bit, but not for a day or two. I'd suggest you do the transfer only an hour or two before you put the cake out, if possible. Best of luck. PLEASE post a picture afterwards!