Whisk together the olive oil, jalapeño, garlic, black pepper and turmeric in a small bowl. Pour into a gallon-sized resealable zipper storage bag or a bowl. Next, add to the bag or bowl the chopped cauliflower. Shake or toss gently, ensuring that the florets are well-coated. Place coated cauliflower in a medium baking dish, single layer. Roast until lightly golden brown and just tender, 25 to 30 minutes. Check halfway through cooking and turn or flip florets if necessary.
Serve warm, as a side dish or add your favorite protein to make it a main dish.