You can use any kind of sweet potato for this recipe! However, my favorite kind of sweet potatoes EVER and the one that I use for nearly everything sweet potato related are Japanese Sweet Potatoes. They are a little bit sweeter than traditional sweet potatoes here in the US, but they also have a religious delicious nutty flavor that is often compared to a roasted chestnut. If you haven’t tried them, I highly recommend! Whichever potatoes you use just be sure that they are fairly uniform in shape and thickness (though not too thick!) so they cook evenly.