I use cannabutter regularly. I can't see why you would put plant matter in the cookies too. That's the whole idea behind making the butter, so you don't have to include the plant matter. But to each his own.
I've used the stovetop boil with water method, but now I use a crockpot. That way I can use butter only, and it won't burn. I powder the bud/leaf in a food processor, and I mean to a flour-like powder, and mix with the butter. I heat for 4 hours, and stir every 15 minutes. Sqeeze it all thru some cheesecloth, and you're ready to bake.
One more thing, when you cook with cannabis on a stovetop or countertop, it's best to not do it in bright light. Low light/dark is best, because when cannabis is wetted, bright light will degrade the potency.