In a medium microwave-safe mixing bowl, add chocolate, butter, and vanilla extract. In a small pot, combine cream and coffee extract and heat over medium heat to a simmer; do not let it come to a boil. Pour over chocolate mixture. Let sit 30 seconds and then stir to melt the chocolate. If chocolate does not melt entirely, you can carefully heat in microwave, in 20 second intervals, until it is completely melted.