Preheat the oven to 425°F (220°C).
Toss the cauliflower florets with olive oil, salt, and black pepper on a baking sheet.
Roast the cauliflower in the preheated oven for 20-25 minutes, until tender and caramelized.
While the cauliflower is roasting, prepare the tahini sauce. In a bowl, whisk together tahini, lemon juice, garlic, and water until smooth. Add more water if needed to reach the desired consistency.
Once the cauliflower is done, drizzle it with the tahini sauce and garnish with chopped parsley.
Serve immediately and enjoy!