You start by melting the chocolate and butter with the sugar in a double boiler. Here's a tip - if your glass bowl isn't Pyrex, DO NOT USE IT for a double boiler. I discovered this when I heard the ominous
Until it was time to taste. Umm...I don't think you should try to substitute unsweetened chocolate for bittersweet. My brownies were intensely over-cocoa'd. So intensely that I had to throw them out. However, I'm definitely going to try them again (with the right chocolate!), because the pomegranate and chili really went well with the chocolate.