Simmer a pot of water with the rest of the ingredients. (happyandharried.com)
In a small, heat - proof bowl, place the butter and chopped chocolate, and place over a simmering pot of water, making sure the water doesn't touch the bottom of the bowl. (glutenfreeonashoestring.com)
Add in the butter pieces and set the bowl over the simmering pot of water. (aclassictwist.com)