HERE. I have read that the Brewer's Yeast is one of the most important ingredients in this recipe as far as a boost in milk is concerned. However, I bought Nutritional Yeast out of the bulk bins at Winco since I couldn't find Brewer's Yeast (and I figured they were fairly similar as far as nutrition goes) . Nutritional Yeast is different than regular yeast, and is much more expensive, so if you can find it in a bulk bin you can just buy what you need (2-4 TBS).
Let me tell you, these taste soooo good. My entire family likes them! It would be no problem at all for me to add this in to my daily diet ;)
The recipe says to bake each batch for 12 minutes, but if you like softer cookies, I found 10 minutes to be perfect.