Wash the cauliflower and cut it into medium-sized florets.
In a large mixing bowl, combine the olive oil, ground cumin, ground paprika, ground turmeric, red pepper flakes, salt, and black pepper.
Toss the cauliflower florets in the spice mixture until they’re thoroughly coated.
Spread the coated florets on a baking sheet in a single layer, ensuring they aren’t overcrowded.
Roast the cauliflower in the preheated oven for about 25-30 minutes or until they are tender and have a nice golden-brown color. Remember to flip the florets halfway to ensure even roasting.
While the cauliflower is roasting, prepare the tahini drizzle. In a bowl, whisk together the tahini, lemon juice, minced garlic, and warm water. Adjust the consistency with water and season with salt.
Once the cauliflower is ready, remove it from the oven.
Serve the spicy roasted cauliflower on plates or in a bowl and generously drizzle the tahini mixture over the top.