¼cupof finely grated fresh horseradishI highly recommend a Microplane grater
1tablespoonof shirowhite miso
3small radishestrimmed and sliced as thinly as possible (I used a mandoline)
1tablespoonof soy sauce
Kosher salt and black pepper
Put the finely grated horseradish in a plastic bag and put it in the freezer.
Put the sliced radishes in a small strainer and toss with a few pinches of salt. Set aside.
Put the water and miso in a saute pan or skillet and bring to a boil over high heat, stirring to dissolve the miso.
When the miso mixture is boiling, add the snap peas and cook, stirring often, until the peas are bright green, around 2 minutes. Reduce the heat to medium and add the soy sauce, stirring until the peas are well coated with the liquid, another minute. Remove from heat.
Put the now-frozen horseradish in a food processor (if you have a mini-prep one, use that), and whizz it until the horseradish is super-finely ground. (Be careful not to overdo it, or the horseradish will get all clumpy.)
Put the snap peas and their broth in a bowl, top with the radishes (you may want to blot them dry if they're super wet), add a few turns of black pepper (and salt if you feel like it's necessary but given the salted radishes and the fact that miso's pretty salty to begin with, you should probably taste before adding additional salt), top with the horseradish, and serve immediately or at room temperature.