Shred (!) the broccoli, the cabbage and the onion in your food processor. I had to do this a li'l bit at a time due to my mini food processor. I should really invest in a proper sized food processor!
Throw that in a big bowl and mix it up.
I used the food processor and added the dressing ingredients (to use up the stuff I couldn't scrap out) - garlic, ginger, chilli, sesame oil and coconut aminos.
Throw that in with your shredded veg, and sprinkle the sesame seeds on top.