If you chop the broccoli (or brussels sprouts, kale, collards, cauliflower, or any other cruciferous vegetable) and then wait forty minutes, you can cook it as much as you want. At that point, the sulforaphane has already been made, so the enzyme is no longer needed to achieve maximum benefit. It’s already done its job. (You can also buy bags of fresh greens and other crucifers that are prechopped or shredded, which can presumably be cooked immediately.)
