When it calls for certain ingredients and does not suggest substitutes, I stick to the original ingredients. You can always doctor it up later to your own tastes but I have found in the past when you do to your own taste you really never find out if it's that good. I have seen this recipe and it's great. Best brownies I've ever made. I have used Splenda and pitched it. Way too sweet for me. DH is not good with fine, he wants great!