For the florets: Line a large baking sheet with parchment paper. Preheat oven at 220°C/425°F
Rinse cauliflower florets and drain in a colander. Cut bigger ones into halves or quarters. Tap dry and transfer onto the prepared sheet. Sprinkle with some salt and pepper, drizzle with 4 tablespoons of sunflower oil. Toss florets with your hands to coat them with oil, and spread them in an even layer.
Roast in the upper half of your oven for 15 minutes. Remove the baking sheet from the oven. Use tongs to turn over the florets. Return to oven and continue roasting for another 15 minutes, or until tender, caramelized and crispy on the edges. Place the florets in one layer in a 24-cm round baking dish
For the tarator: In a mixing bowl add tahini sauce, water, lemon juice, garlic and ½ teaspoon of salt, and whisk until smooth and creamy. Add a bit of water if too thick.
For the tajen: Preheat oven (200°C/ 400°F). In a small frying pan heat 2 tablespoons of sunflower oil over medium heat, and sauté nuts for about 3 minutes until golden in colour, stirring all the time. Remove onto a plate.
In the same frying pan sauté the onions and chilli flakes for about 5 minutes, or until wilted and slightly brown. Remove from heat and pour in the tarator and stir to coat all the onions. Evenly pour the creamy sauce over the roasted florets in the baking dish.
Bake for about 20 minutes until the sauce is golden brown on top. Transfer onto a serving platter, garnish with nuts and parsley and serve hot or at room temperature with Arabic bread.