Generously butter the bottom and 2 inches up the sides of the insert of a large slow cooker.
In a large bowl, whisk together eggs and sugar until pale and foamy. Beat in milk, cream and vanilla.
Scatter bread cubes in slow cooker. Pour milk mixture over bread. Avoiding the sides of the cooker, dot the surface with jam.
Cover and cook on HIGH for 3 hours or until center is just set. Serve warm with whipped cream and fresh raspberries, if you like.