Trim the cauliflower florets by removing as much of the stem as you can. The florets should be divided into three batches and put in a food processor. Pulse the mixture until it resembles couscous.
In a big skillet over medium-high heat, warm the oil. Add the onions and toss to coat when the oil begins to smoke for the first time. For about 8 minutes, sauté the onions, stirring often, until they are tender and beginning to become golden. Stir in the cauliflower after adding it. Add 1 teaspoon of salt, and boil the cauliflower for an additional 3 to 5 minutes while stirring often. Get rid of the heat.
Place the cauliflower in a sizable serving bowl, top with the parsley, squeeze in some lemon juice, and season with salt and pepper as desired.