Preparation Preheat oven to 350°F. Butter 13x9x2-inch metal baking pan. Soak raisins in rum in bowl until plump, about 30 minutes. Stir butter and unsweetened chocolate in heavy medium saucepan over low heat until smooth. Cool slightly. Whisk in sugar and eggs. Mix in raisins with liquid, then flour. Mix in chips. Transfer batter to pan. Bake until tester inserted into center comes out with moist crumbs attached, about 20 minutes. Cool brownies in pan on rack. Cut into squares.
Preparation Preheat oven to 350°F. Butter 13x9x2-inch metal baking pan. Soak raisins in rum in bowl until plump, about 30 minutes. Stir butter and unsweetened chocolate in heavy medium saucepan over low heat until smooth. Cool slightly. Whisk in sugar and eggs. Mix in raisins with liquid, then flour. Mix in chips. Transfer batter to pan. Bake until tester inserted into center comes out with moist crumbs attached, about 20 minutes. Cool brownies in pan on rack. Cut into squares.