In a large bowl, whisk together the milk and eggs until completely blended.
Stir in the vanilla sugar.
Slowly whisk in the flour until incorporated without any lumps, then the salt, and finally the melted butter. The batter should be thin.
Place a towel over the bowl and allow to rest at room temperature for 1 hour.
Place a Plättlagg over medium low heat.
Once heated, very lightly grease the cavities with butter.
Stir the rested batter briefly to make sure it is evenly combined. Fill each cavity with about 2 tablespoons (30 milliliters) of the batter. It should spread to create a thin pancake. If it doesn't spread, gently tilt the pan to create an even layer.
Once the top is nearly set, but still a little wet in the center, use a small spatula to gently flip the pancakes to the other side. Cook until lightly golden, then remove to a plate.
Repeat with the remaining batter, lightly greasing the pan with more butter between batches.
Serve warm with jam, whipped cream, and/or other desired toppings.