Preheat oven to 350°. Grease a cookie sheet.
Cream butter in a large mixing bowl. Drizzle in melted chocolate and beat well. Add sugars, molasses, and egg. Beat several more minutes, Stir in vanilla.
In a separate bowl sift together flour, baking soda, ginger and salt. Stir this into the first mixture. Mix thoroughly but briefly, just enough to combine.
Lightly flour your hands and form 1 inch balls. Place them about 2 inches apart on the greased cookie sheet. Bake for 12 minutes at 350°. Cool on a rack.