Separate the eggs into whites and yolks. Whisk the egg whites stiff. In the bowl with the yolks, add all remaining ingredients and whisk together into a smooth batter. Gently fold in the egg whites. The egg whites make them fluffy and help retain the round shape during frying. Heat an aebleskiver pan well, put a small piece of butter in each hole and fill them 2/3 full with batter. When they have a crust, carefully turn them halfway around (I use a toothpick). Add a little more batter in the middle, fry for about 1 minute, and turn completely. You should now have a nice round aebleskive. Turn them a few more times until they are fully cooked and have a nice golden color. Serve with jam and powdered sugar.