Trim rind from top of Brie round. Place Brie on a lightly greased baking sheet. Bake at 400° for 7 minutes or until cheese is just melted. Meanwhile, microwave Cardamom-Plum Jam, grated onion, vinegar, salt, and pepper in a microwave-safe bowl at HIGH 1 minute or until smooth, stirring at 30-second intervals. Place Brie on a serving dish; immediately top with warm jam mixture. Serve with crackers and fresh fruit.