I've been playing with making extra-strength butter lately & took some pics of the last batch I made which turned out pretty well.
I'm using dry sift jamaican, get lots of it & don't smoke it because good bubble is so much nicer.
I use the double broiler way & put a bowl on top of a boiling pot to heat it up without burning it, start with 2 cups of hot water & add in 1/2 to 3/4 of a lb of butter. melt in the butter then dump in the kief. I'm using 150 grams in this batch, I found using any more than about 1/2 lb kief to a lb of butter & the butter won't solidify again.
I keep stirring & let it steep for an hour or so then dump it all through the strainer (I usually use a few layers of cheesecloth, but realized I didn't have any after I was cooking this so used a t-shirt), & into a cup so it can go in the fridge & harden up.