One idea -- if you are set on not adding water to the butter or oil (I guess with oil it makes sense -- it will be harder to extract from water, but you can probably do it in the freezer):

Use a candy thermometer. You can get one at most supermarkets for $4, and they clip on to the side of a pot. Then you can keep your oil < 300 F.

Keep in mind -- if you are using straight butter or oil and use "simmering" (small bubbles) as an indicator, that's too hot. Oils tend to bubble at > 400 F.

I just think the recipe posted here is as good as it gets. You have guaranteed results with this method, so long as you use good ingredients.

Good God -- even 1/2 a cookie is starting to hit me hard right now, and the peak is about 30 minutes away (usually peak is 90 minutes after eating, and tends to last 2 hours). And I'm just using peppermint!