After quartering cabbage, use the finest setting on your mandoline to shred about 1/2 of the cabbage - about a full gallon ziplock bag full.
Do the same with 1/4 of the red onion.
In a small sauce pan, add rest of ingredients and bring to a quick boil. Turn off heat and allow to cool 15 minutes.
Toss cabbage and onion in a large bowl with the liquid. Refrigerate at least one hour, preferably 4-6.
Notes
Yes, you can make this recipe easier with a bag of precut angel hair slaw from the grocery. But I've found the bagged cuts to be really inconsistent and chunky.Please, please be careful with the mandoline. They are notorious for taking the tips of your fingers off! I like this simple one.