Slice the cauliflower head in half and use a knife to remove all the florets. Cut some of the larger florets into smaller pieces so they'll fit within the chute of your food processor.

Insert the grater adapter into your food processor and start feeding the cauliflower florets through the top. Depending on the size of your food processor, you may have to empty it halfway through.

Heat the olive oil in a large pan and sauté the diced onion for a few minutes, until its translucent.

Add the cauliflower rice to the pan and sauté for another 5-7 minutes.

Season with salt and pepper and serve immediately.