Using a food processor, or by hand, chop 1/2 head of a cauliflower into coarse crumbs. In a frying pan, on medium heat, with a tablespoon of olive oil, sauté a bit of finely chopped onion (optional) for 1-2 minutes, and then add the cauliflower. Stir occasionally for even cooking, cook until soft. Season to taste.
I made a batch the other night for dinner (from a giant local cauliflower) and had some leftover – just enough to try out a couple of gluten-free, all-veggie sushi rolls. You need very little to make up the filling, but you may need to squeeze out any excess water out of the cauliflower before spreading it on to the seaweed. Here, I found whatever I had in the fridge – thinly sliced red cabbage, cucumber, carrot, summer squash and leftover roasted sweet potato and butternut squash. My avocado wasn't ripe, otherwise I would have added that too. Basically anything goes, but eating a variety of colors (a rainbow!) not only makes your food look amazing, it also ensures you are getting a variety of nutrients.