Combine raisins and rum in a small bowl; let soak for 30 minutes, then drain.

Beat eggs, milk, white sugar, vanilla, and salt together in a medium bowl; gradually whisk in flour to make a smooth batter. Stir in drained raisins.

Melt 2 tablespoons butter in a large skillet over medium heat; pour batter into the skillet and cook 5 to 6 minutes, or until the pancake has set and the bottom is golden brown. Flip pancake and cook until this side is also golden brown, about 3 minutes.

Tear pancake into bite-sized pieces using a spatula or two forks; drizzle in melted butter and sprinkle with confectioners' sugar. Increase heat to medium-high and gently toss the pancake pieces until sugar has caramelized, about 5 minutes.