How to Make Sudachi/Key Lime Pie in Japan

    The first time I saw sudachi in the grocery store in Japan, being sold in small bundles for 100 yen each in mid-summer, I thought they looked a lot like key-limes and it took a full year for me to get up my baking confidence enough to actually test my theory.  

    Sudachi are small, round, sour citrus fruit usually sold and used while green but will turn yellow-orange over time (and will likely still be usable at that time) and tend to be used in place of lemon or lime in many Japanese dishes. Plant geeks may have long, detailed answers as to how and why they are different from key limes, but honestly this explanation (see top comment by Jason Stai) flies right over my head., probably because I have never eaten a citron or a papeda and those are the two important fruit species when it comes to sudachi and key lime.

    Finding a good recipe for key lime pie was tricky because many of them required impossible ingredients like sour cream, which would prohibitively expensive for me to acquire if not home-made, which I am not yet brave enough to attempt.

    I did eventually find this recipe which includes lots of sweetened condensed milk, which is easy enough to find. I highly recommend using a juicing apparatus of some kind because trying to drain these little suckers by hand was a pain with shockingly little yield. Four packs of the little green spheres and I didn't have enough for the full recipe so I halved all the other ingredients as well. 

    Luckily, I had just enough graham crackers left from my summer adventures state-side to make a graham cracker crust, another first for me. This part was actually pretty easy and it's mostly mushing the crackers, melting the butter, and pushing the two together evenly in a pan before baking it for a few minutes in the oven or microwave on "oven" mode.

    One other apparatus related problem I had was caused by the need for zest. I have never had need of a zester. If you're like me, you can substitute finely diced chunks of the actual peel. I didn't think I had diced it finely enough in these pictures but the smallest chunks I could make worked out just fine.

    The instructions suggest an electric mixer which I own but am so incompetent at using that I have never managed to do more than spray the ingredients all over every nearby surface. Instead, I beat the egg with a whisk manually and no, it wasn't all that fluffy, but it worked. Adding the lime juice gradually and not over-mixing while doing so it a good idea that I found easy to follow.

    If your microwave/oven is a little wonky on temperatures like mine is, you might add a few minutes to the cook time but check regularly in any case. Bake it for the suggested time, remembering that this is not the standard cook-till-brown pie. "Cook till set" which I took to mean "cook till it doesn't act like soup if you move the container" which seemed to work okay.

    The instructions are based on American kitchens, so is cooling on a counter is your only option, do that. If freezing it 10 minutes before you serve it is impossible due to the size of your tiny Japanese freezer, forego that step too and serve it out of the fridge. We did that and it was great. Heck, I didn't even make the topping and didn't need it.

    Does it taste like key lime pie? Honestly, I don't know. The last time I had key lime pie was probably about 20 years ago. I don't remember exactly what it is supposed to taste like, but I can tell you that my sudachi pie was delicious.