These are seriously tasty - like a macaroon. The peanut flavor does not come through because I don't much care for peanuts. If you like them, feel free to substitute some or all of the butter in the recipe with peanut butter. You can also sub it out with almond butter if you prefer.
And as far as being effective - well, I had several before bed last night, and let's just say my chubby baby has been feasting royally ever since. I wasn't sure if it was possible to make a lactation cookie without the obligatory oats, but for me personally, this is even more effective than my standard, oat-based recipe.