From google:
Tincture: An alcohol solution of a nonvolatile medicine
In this case it's THC in an alcohol solution. It's pretty easy to make. Basically just put your ground bud/trim in a jar with alcohol. Everclear works best, but you can use any alcohol you like. Make sure it's at least 100 proof, though. Use a ratio of 1oz dried bud to one pint of alcohol. Then just shake the jar up and put it in a warm, dark place. Shake the jar once per day and keep it in the dark, warm spot for 30-60 days. Then just strain out the plant matter and presto! You've got a cannabis tincture. One eyedropper under the tongue will get you where you need to go. Make sure it's under your tongue so it gets directly into your blood vessels. If you swallow it you'll have to wait forever for it to digest.
The cool part about tincture is you can use it anywhere and nobody's the wiser. As far as they're concerned you're taking vitamin drops.
As for your question on which needs more butter, the answer is really specific to the recipe. If you want to add more butter to a recipe you can always do that, but your baked goods might not be as soft. I just buy pre-mixed brownies when I'm feeling lazy. They don't even call for butter, but I add a quarter pound anyway, since their ingredients don't include the one I really want to get in there.
If you need recipes, check
http://www.allrecipes.com They've got pretty much everything in there.