Preheat oven to 425 degrees Fahrenheit.

Toss cauliflower on a baking sheet with two tablespoons olive oil, harissa, cumin, paprika, 1 teaspoon salt, 1/2 teaspoon pepper and coriander until evenly coated. Roast for 25 to 30 minutes, until cauliflower is tender and caramelized, tossing halfway through.

Meanwhile, toss tomatoes on a second baking sheet with remaining one tablespoon olive oil, herbes de provence, remaining 1/2 teaspoon salt and remaining 1/4 teaspoon pepper. Roast for about 15 minutes, until softened and slightly caramelized.

Transfer roasted cauliflower and tomatoes to a serving platter. Drizzle with tahini sauce and harissa sauce. Garnish with parsley and sesame seeds.