Bud Butter is essential if you are going to make and eat your own edibles. There are a couple of methods, but I recommend the "water" method if you want to play it safe!
First, you need to buy the finest products. European Butter is much more expensive, but it is estimated to have 15%-20% more fat. That's the key, it's the fat that absorbs the cannaboids from the plant. It is equally important to use good plant product. I prefer a shake/bud mix to produce a pound of butter, I recommend 14oz total.
EVERYONE, seems to have their favorites. This is a guestimate - obviously each plant has a different personality, so does the products it produces.
Place 1# butter with ground plant product(s) and a gallon of water in a large pot on a Med High burner. It is important to control the heat - @ 350 degrees, the THC starts to break down - be patient - you will not be happy with the results if you try to hurry this process. Let pot and contents simmer until all the water has evaporated. Strain the liquid concoction through a strainer lined with cheesecloth into a vessel that will hold your measured finished butter (1/4 C. glad containers work really well). I pour boiling water over the cheesecloth mess to separate the last bit of the butter from the plant product.