Some people will parboil vegetables before roasting. Parboiling is, basically, cooking the vegetables in boiling water until they're soft. I don't do that with these carrots. They cook through really well, so I personally don't think it's necessary. If you want to, go right ahead, but that does take longer and does mean you're also washing a pot and I just don't want to do all of those things. All that being said, if I'm using fresh Brussels sprouts, I actually will parboil them before cooking. If I'm using frozen Brussels sprouts, I don't. So honestly, this is really a case by case thing and totally up to you.