Separate the eggs. Put yolks in one bowl and whites in another.
Whip the egg whites until soft peaks form. Set aside.
In the yolk bowl, whisk milk, melted butter, and vanilla.
Add flour, sugar, baking powder, and salt. Mix until smooth.
Gently fold the whipped egg whites into the batter. Don’t stir hard.
Heat a Danish aebleskiver pan over medium heat. Butter each well.
Fill each well about 3/4 full with batter.
Cook until edges set and bubbles appear, about 1–2 minutes.
Use a skewer to turn each pancake a quarter turn.
Keep turning until each ball is fully round and golden.
Remove from the pan and serve warm with powdered sugar or jam.
