In a small bowl combine raisins with rum and let soak 30 minutes then drain.
In a medium mixing bowl beat together the milk, eggs, white sugar, vanilla and salt. Gradually whisk in the flour to make a smooth batter. Stir in the drained raisins.
In a large frypan melt 2 tablespoons butter over medium heat. Pour the batter into the frypan and cook 5 to 6 minutes or until the pancake has set and the bottom is golden brown. Turn over the pancake and cook 3 minutes or until the other side is also golden brown.
Using a spatula or two forks tear the pancake into bite-size pieces. Drizzle in the melted butter and sprinkle with icing sugar. Turn up the heat to medium high and use a spatula to gently toss the pieces for 5 minutes or until the sugar has caramelized. Sprinkle with additional icing sugar and serve with plum jam.