Pulse a small head of cauliflower in the food processor. You want it to be a rice like texture. Make sure to not over pulse. A small head should measure out to 2 1/2 cups - more or less is fine.
Then either chop the carrots, celery and onion or you can pulse each of them in a food processor to get them finely chopped. It's much easier to do it that way to me.
In a large bowl mix everything together. You can add other things like raisins, currants or different veggies you might like. Enjoy!