Whisk together first four ingredients. In another bowl, whisk together flour, cocoa, coffee granules and salt; gradually beat into egg mixture. Transfer to a greased 1-1/2-qt. slow cooker., Cook, covered, on low until a toothpick inserted in center comes out with moist crumbs, 2-1/2 to 3 hours. Serve warm. If desired, serve with ice cream and raspberries.