Add the milk, breadcrumbs, 25g of the caster sugar and the melted butter to the slow cooker while it is turned off, and stir well. Allow to sit for 10 minutes so the liquid is fully absorbed.
Once absorbed, stir through the egg yolks, then carefully spread the jam over the top. Cook on high for 1 hour or low for 2 hours.
When the mixture is nearly ready, whisk the egg whites to stiff peaks and gradually whisk in the remaining 75g of caster sugar until glossy and thick.
Spoon the meringue onto the top of the pudding in an even layer and cook on high for another 30 minutes or low for another 1 hour.
Just before serving, place the slow cooker pot (make sure it’s ovenproof) under a medium grill for a minute or so until the meringue is lightly browned.
