In a large bowl, combine 3/4 cup sugar, plums, cornflour and cinnamon. Place fruit mix in slow cooker. I used a 3.5 litre slow cooker.
In a medium bowl, combine the remaining 2tbs sugar, flour, baking powder and salt. Cut the butter in with a fork or pastry blender until the mixture resembles coarse breadcrumbs. Stir in the milk and egg until just moistened.
Drop batter on the fruit. I used a dessert spoon and randomly plonked spoonful's on top of the fruit.