We don’t recommend canned vegetables for this recipe or any others. Canned vegetables sit on the shelf at the store for a long time, and in people’s pantries much longer. They also often have lots of sodium and extra preservatives. The cauliflower is fresh when it is canned, but loses most of its natural crunch as it sits soaking in a suspension of saltwater. Frozen vegetables, on the other hand, are usually the freshest vegetables in the store. They are often frozen almost immediately after their harvest and retain a consistent temperature until cooked and served. Fresh vegetables are subject to travel time from the farm to the store, and a lot of things can happen along the way. But they are still the best option for this recipe, and should only be substituted if you can’t find a good looking fresh floret in the produce section during certain times of the year.