Preheat the oven at 400 deg F. Line a cooking sheet or baking tray with aluminum foil and grease it with oil. Now add the cauliflower florets to the lined baking tray.
Add the olive oil, salt, and sumac. Mix it thoroughly with hands. Make sure you rub and evenly coat the florets with oil, salt, and sumac.
Bake it at 400 deg F for 15 minutes and remove it from the oven. Gently toss/flip the cauliflower florets.
Bake it again at 400 deg F for 15 minutes. We are baking for 30 minutes at 400 deg F flipping them once half-way through.
Garnish it with chopped parsley leaves and serve it as a side or let it cool a bit and add it to your salads.
Notes
As I mentioned before, you can add spices of your choice instead of sumac. Adjust the amount according to your preference, and the same goes for the salt as well.
If you prefer a crisp cauliflower, bake for an extra 5 to 7 minutes.
You can add ⅛ tsp of turmeric powder for that beautiful yellow hue.