Melt the chocolate and butter over a double boiler or in a small bowl in the microwave, stirring often.
Mix together the dried cherries and pistachios and spread thinly on a piece of parchment paper in a rectangle.
Pour the melted chocolate evenly over the rectangle, fold the edges of the paper over each side and press down to remove air and distribute the chocolate.
Refrigerate until firm, at least 30 minutes. Roughly break apart and serve.
Store in an air-tight container in the refrigerator.
Notes
Gluten free, Kosher dairy, Vegetarian
Recipe by Katherine Martinelli at http://www.katherinemartinelli.com/blog/2012/pistachio-cherry-and-dark-chocolate-bark/