If using spring cabbage, cut out and discard the thick stem from the center of each leaf. Lay the leaves on top of each other, roll them up and slice as thinly as possible. You should end up with 1 - 2 mm strips of cabbage. If using kale, strip the curly leaves from the stems and break them into small pieces. If using dried seaweed, separate it into strands following the line of the "hair" and then cut it into 1/6-in (5m) pieces.
Put the peanuts in a seasoned wok with the cooking oil and heat gently to 260 - 275 degrees F (130 - 140 degrees C) until there is a gentle fizzing around the nuts -- it's easiest to use a thermometer for this. Deep-fry at this temperature for 15 - 20 minutes, until the nuts are glossy, crisp and fragrant (if you taste one, carefully, you will be able to tell when it has lost its raw crunch). Remove with a slotted spoon and drain on paper towels.
Reheat the oil to 350 degrees F (180 degrees C). Add the cabbage or kale in two or three batches and deep-fry for a couple of minutes, or until crisp. Remove with a slotted spoon and drain on paper towels. If using seaweed, heat the oil to 300 - 320 degrees F (150 - 160 degrees C) and deep-fry very briefly until crisp. Remove with a slotted spoon and drain on paper towels.
Mix the peanuts and cabbage "seaweed" together, season with salt, then add the sugar and serve. If you are using real branched string lettuce, you won't need any salt.
"Land of Fish and Rice" by Fuchsia Dunlop © W.W. Norton & Company 2016. Provided courtesy of Fuchsia Dunlop. All rights reserved.