Combine first 4 ingredients in a 3-quart saucepan. Bring to a boil over medium heat, stirring occasionally. Cover; reduce heat to low.

Meanwhile, combine flour and next 3 ingredients in a bowl. Add milk and butter, stirring until smooth. Spoon dumpling mixture over berry mixture. Cover and simmer 15 minutes. (Do not remove cover.) Dumplings are done when a knife inserted in center comes out clean. Serve warm with sweetened whipped cream, if desired.