September 29, 2010

Superman Kryptonite Cake (and Sugar Glass Recipe)

This is one of the first cakes I made (2009) and I had so much fun trying to figure out how to get everything I wanted to do made in sugar!  I knew I wanted to make something unique and different for a friend's can, and this is what I came up with, a Kryptonite Superman Cake!  I spend weeks researching sugar glass and gelatin in figuring out how best to make Kryptonite crystals that were edible and tasty.  You just know there will be a kid who is going to try and eat it!

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Making the Kryptonite:  I originally tried making them from gelatin sheets that I trimmed into the shape of crystals but they just tasted awful and looked nothing like a crystal, at least the way I was envisioning the kryptonite to look.  After failing at finding any possible "crystal" mold, I improvised and made my own mold using an oven rack and foil.  The foil was dented in between each section to form a well for the sugar to sit in and the ends were curled up to help contain any sugar that may want to seep out past the well.  The foil along the sides were tightly tucked under to hold up the weight of the sugar.  PLEASE take precaution when working with hot, molten sugar!!!  It is dangerously hot.  Wear safety gloves specific to working with sugar (or isomalt) and have all your stuff ready and in one place so you can easily grad what you need without much movement around and risk spilling this stuff... just be super careful!

Sugar Glass Recipe:
1/2 Cup Sugar (see note below)
1/2 Cup Light Corn Syrup
Melt the sugar and corn syrup into a sauce pan over medium heat.  Use a candy thermometer to check the temperature and boil the mix until it reaches 300° (hard crack stage).  Add any coloring and/or any flavor oils.

NOTE:  Do not add the coloring before 300° or else the finished, cooled product will be tacky.

NOTE:  Granulated sugar turns a golden yellow color when boiled.  If you want it to remain clear, you will need to use Isomalt (sugar free).

Note:  If the sugar glass looks a little cloudy once it's hardened, you can rub and polish it with a tiny bit of vegetable oil.

I used regular granulated sugar since I was coloring it green using ChefMaster Green Candy Colors.  The ChefMaster candy colors do not have water in them and work well with coloring sugar, chocolate, or fondant with.  Their colors are vibrant and a very tiny drops, goes a long way.

I lightly brushed the foil mold with vegetable oil so that the sugar wouldn't stick to it like glue and poured the hot, 300° sugar syrup carefully over each well.  Pour it in a slow thin stream to avoid getting air bubbles in the mold.  Let it sit for about an hour until completely cooled and hard.  Then, peel the sugar glass off the foil.  Store the sugar glass in an airtight container with a food safe silica gel packet to keep it from absorbing moisture.  Moisture will make the crystals sticky/tacky and putting them in the fridge will melt them...did you watch the Cake Boss episode where he used isomalt to make coral for an aquarium cake?  I got my silica gel packet from inside those Nori Packets (the seaweed sheets used to make sushi).

Break off the crystal sugar pieces and apply them to the cake.  I found that the best thing that worked at holding the sugar glass up against the fondant cake were tiny little pieces of fondant brushed with a little bit of water.  Icing didn't work...well, it didn't stick to the sugar glass, and straight water did nothing.  I'm sure you could use piping gel but I didn't have any on hand when making this cake.

Superman Cake Topper:
I made him out of fondant building up his key features layer upon layer and placing them side by side like a puzzle.  I then scored in the details and painted in the details using gel colors diluted with almond extract (you can use Vodka but I didn't have any on hand and almond or lemon extract evaporates quickly leaving no residue behind).  Don't use water to paint over fondant, it eats away at the fondant and will leave a tacky mess behind.

The entire cake was covered in buttercream then with yellow-green tinted MMF.  I originally wanted to make it blue but the green sugar glass did not look good up against it so I modified the design and came up with this color made with both AmeriColor Electric Green and Wilton Bright Yellow.

I made some skyline silhouettes of buildings to add around the back of the cake.

The Superman symbol was cut free-handed into a"2" for the little boys 2nd birthday.

Finished off with more Kryptonite around the front of the cake.  Notice the Daily Planet globe on top of the building =)?  I love adding those tiny details that pull a theme together!

Cake:  9" Chocolate Sour Cream Cake filled with White Chocolate Mousse.


  1. kryptonite is a master touch!

  2. Holy smokes...just what I was looking for! Doing a Superman groom's cake and thinking of adding skyline and crytals from krypton. Thanks a zillion!!

  3. Ok, this is awesome, but kind of scary. I wanted amethyst crystal spikes on my wedding cake in clusters like how they look naturally, and I'm even willing to get plastic prop ones. I really want them to look as real as possible, zoned and everything (that means how it gets a deeper color towards the tip and almost clear towards the base), but I can't find ANYTHING! I think sugar molds are my best bet, like this recipe you gave, but I was hoping for larger crystal clusters. Any tips?

  4. @ geojan224. Sounds tricky. If you have the plastic ones, you could make a mold out from them, get an extra set of hands and heat up both clear and dark sugar, pour at opposite ends and hope they blend into each other smoothly. Haven't tried it but let me know what you end up doing. Good luck!

  5. Thank you for this! I've been looking everywhere for a simple kryptonite recipe. My niece is turning 21 this week and wants a Superman cake. I guess you really never grow up, right? :)