My son left it wide open for me this year. He wanted his usual spice cake (the one I’ve marked with his name in the cookbook), but he left it up to me how I decorated it.

I swear that was more difficult than being told what he wanted.

After many hours scouring the cupboards and looking at cake photos online for inspiration, I came up with a large geode.

Most geode cakes online are, frankly, weird—an ordinary tiered cake covered smoothy in fondant, with a slash down the side filled with geode crystals. They don’t look like a geode at all, and some look disturbingly like vaginas. I didn’t think my son would appreciate that. I strove for a more natural geode look.

I also hoped for a tastier geode material. I was inspired to do a geode by a bag of crystalised ginger in the cupboard. Most geode cakes, though, are made with rock candy, which isn’t the nicest accompaniment to cake. On a spice cake, I thought crystalised ginger would be a much more appropriate flavour (and texture). Unfortunately, my experiments with colouring ginger were uninspiring—the ginger had a beautiful sparkling appearance, but light colours looked grey on the yellowish ginger, and dark colours looked black. I couldn’t manage a nice geode-like lavender.

So I made purple hard candy and broke it into shards for the crystals.

The result was reasonably geode-like, and easy to make. And better than a crystal vagina.