It depends on how you cook the cauliflower. To preserve most of its nutrients, it's best to microwave, roast, air-fry, or steam the cauliflower. The gentlest is microwaving, preserving almost all antioxidants. Boiling and pressure cooking will result in some loss of nutrients as vitamins and minerals leach into the cooking water (although it is better to eat boiled cauliflower than no cauliflower as only about 14% of nutrients will be lost).