Assemble, prepare, and measure ingredients. Break cauliflower into florets and spread onto two ungreased baking sheets. Roughly chop cilantro and mint. Preheat oven to 425°F/220°C.
For the cauliflower, pour olive oil into a small bowl, stir in cumin and turmeric, and season with salt and pepper. Spoon spiced olive oil over cauliflower and toss to coat florets evenly. Roast for about 45 minutes, checking occasionally to confirm cauliflower isn’t burning. Do not turn cauliflower unless you want even browning. If you ask me, it’s more interesting to have a darker brown side—and it’s less work for you!
For the tahini sauce, place garlic cloves in a mortar or on a wooden board. Add salt, 1 teaspoon at a time, and use the pestle or flat side of a knife to break down garlic and make a paste. In a small bowl, stir this garlic paste with tahini, lemon juice, 1/4 cup/60 mL water, and olive oil. Set aside.
Toss roasted cauliflower with chopped herbs, transfer to a serving platter or individual bowls, and serve with tahini sauce on the side.