Remove tough outer leaves from 1 small green cabbage (about 2 lb) and cut into wedges you can hold safely.
Grate cabbage on the large holes of a box grater into a large bowl (about 8 cups shredded).
Grate 1 large carrot (about 1 cup) into the same bowl. Add ¼ small onion, very thinly sliced, if using.
Add ⅓ cup apple cider vinegar, 2 tablespoon sugar, 1½ teaspoon kosher salt, 3 tablespoon neutral oil, and ½ teaspoon celery seed if using.
Toss firmly until the cabbage begins to soften and release a little liquid.
Rest 15–30 minutes, then toss again. Add 1–2 tablespoon chopped parsley if using.
Food Processor Method
Remove outer leaves from 1 small green cabbage and cut into chunks that fit the feed tube.
Shred cabbage using the shredding disc (about 8 cups). Transfer to a large bowl.
Shred 1 large carrot (about 1 cup) using the same disc. Add ¼ small onion, thinly sliced, if using.
Add ⅓ cup apple cider vinegar, 2 tablespoon sugar, 1½ teaspoon kosher salt, 3 tablespoon neutral oil, and ½ teaspoon celery seed if using.
Toss thoroughly until evenly dressed.
Rest 15–30 minutes, then toss again. Add 1–2 tablespoon chopped parsley if using.
Notes
NotesDo not salt and squeeze the cabbage for this style. The slaw softens gradually in the dressing and keeps its crunch.If the slaw looks too wet after resting, spoon off a small amount of liquid—do not drain completely.Storage: Refrigerate in a covered container for up to 3 days. Stir before serving. Flavor improves after the first hour.