1small to medium head Napa cabbage, discoloured or loose outer leaves discarded2 tbspkosher or coarse sea salt½ cup plus 2 tbspsugar20garlic cloves, minced20 slicespeeled fresh ginger, minced½ cupkochukaru (Korean chilli powder)¼ cupfish sauce¼ cupusukuchi (light soy sauce)2 tspjarred salted shrimp½ cupspring onions, coarsely chopped (greens and whites)½ cupjulienned carrots
Cut the cabbage lengthwise in half, then cut the halves crosswise into 2.5cm-wide pieces. Toss the cabbage with the salt and 2 tbsp of the sugar in a bowl. Let sit overnight in the refrigerator.
Combine the garlic, ginger, kochukaru, fish sauce, soy sauce, shrimp and remaining ½ cup sugar in a large bowl. If it is very thick, add water 1/3 cup at a time until the brine is just thicker than a creamy salad dressing but no longer a sludge. Stir in the spring onions and carrots.
Drain the cabbage and add it to the brine. Cover and refrigerate. Though the kimchi will be tasty after 24 hours, it will be better in a week and at its prime in 2 weeks. It will still be good for another couple weeks after that, though it will grow incrementally stronger and funkier.