Preheat your oven to 350F and arrange the cauliflower florets into a single layer on a large rimmed baking sheet. (You may need to use two pans to fit them into a single layer, depending on the size of your cauliflower and baking sheets.) Drizzle the cauliflower with the oil and use your hands to toss the cauliflower directly in the pan, making sure to rub and coat the vegetables evenly in oil. Sprinkle generously with sea salt and pepper, as desired.
Place the pan(s) in the center of the preheated oven and roast for 35 to 45 minutes, until the cauliflower is golden and tender enough that it is easily pierced with a fork. (The smaller you chop the florets, the faster they cook-- so, the smaller the better!)