Preheat oven to 425°F (220°C) and line a baking sheet with parchment paper.
Remove the green leaves from the cauliflower, wash it thoroughly, and pat it dry. Trim the stem but leave the core intact. Cut the cauliflower into bite-sized florets of approximately the same size.
Spread the florets evenly in a single layer on the baking sheet without overlapping.
In a small bowl stir together the olive oil with salt and pepper. Drizzle the mixture over the florets and toss to coat evenly. If necessary, toss them with a fork until fully coated.
Roast in the oven for 25-30 minutes, flipping the florets halfway through. The cauliflower is ready when crisp on the outside and tender on the inside.
Garnish with parsley or your favorite seasonings and serve warm.