You always want to get everything you can from your ingredients. Try roasting the cauliflower leaves that come with the head rather than throwing them away.
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You'll end up with tasty greens that you can eat with the cauliflower florets, toss in a warm salad, or eat on their own like chips. You can even roast them with the florets for maximum efficiency. For details on how to best cook them, check out the full post linked below.
Why You Shouldn't Throw Away Cauliflower Leaves [The Kitchn]