In a large mixing bowl, whisk together the flour, baking powder, salt, and sugar.
In a separate bowl, beat the eggs and then stir in the milk.
Gradually pour the wet ingredients into the dry ingredients, stirring until a smooth batter forms.
Heat the vegetable oil in a deep fryer or large pot to 350°F (180°C).
Using a spoon, drop spoonfuls of batter into the hot oil to form small, round Knieküchle.
Fry the Knieküchle for about 2-3 minutes on each side, or until they are golden brown and cooked through.
Remove the fried Knieküchle from the oil and place them on a paper towel-lined plate to drain.
Dust the Knieküchle with powdered sugar before serving.
