Mix the flour with a third of the milk for the dough, eggs, salt and sugar in a bowl. Gradually pour in enough milk to make a thin batter.
Heat a pan and grease evenly with 1/2 tablespoon butter. Pour in a little batter with a ladle and swirl the pan so that the batter flows apart and the bottom of the pan is thinly covered. Bake the pancakes over low heat until golden yellow on both sides.
If the dough thickens in between, stir in some milk again.
Wash the raisins with hot water, pat dry and drizzle with rum. Mix butter with sugar and lemon zest until frothy. Separate the eggs and stir the yolks into the butter mixture. Mix in the curd cheese and the previously drained raisins. Beat the separated egg whites until stiff and fold in.
Preheat the oven to 200 degrees, spread a baking dish with butter.
Spread the filling on the pancakes as thick as a pencil. Roll up the pancakes and cut in half crosswise. Layer the pancakes in the casserole dish with the cut sides facing up, more standing than lying.
Whisk the egg, milk, sugar and vanilla sugar - if you like, beat until frothy - and pour over the pancakes. Place the tin in the oven and bake until golden yellow for about 25 minutes.
Sprinkle the curd pancakes thickly with powdered sugar and serve immediately.