Now we're going to grate or "rice" the cauliflower. You can do this a few different ways: If you have a food processor, you can use the grater attachment OR the blade attachment. If you use the blade attachment, be careful not to blend it too long -- turn the machine off as soon as the cauliflower is in tiny pieces (the size of rice grains or bread crumbs). You can also use a hand held grater -- this takes longer and more muscle, but will do the job. Set the grated cauliflower aside.

Coat the bottom of a large sauté pan with olive oil and place it over medium high heat. Add the mushrooms and cook, stirring often, until golden, about 8 minutes. Sprinkle with a bit of salt and pepper and spoon them into a bowl. Set aside.

Turn the heat to medium and add 2 tablespoons of the butter. Once it's melted, add the onion and garlic and cook, stirring often until they're soft, about 5 minutes.

Now add the grated cauliflower and mix to be sure it's well coated with the onions, garlic and butter. Sauté for a few minutes and then add the stock and sherry. Mix, bring to a boil, and then turn the heat to low-medium, just high enough to keep it simmering. After about 5 minutes, turn the heat up a bit and, stirring frequently, cook until all but a tablespoon or so of the liquid has been absorbed, about another 5 minutes.

Serve!