Husarenkrapfen (German Thumb Print Cookies)
Mix the butter, sugar, vinegar, and water until creamy with an electric hand mixer, then stir in the flour.
Roll the dough into small balls and place on well-buttered baking sheets. Dip a wooden spoon handle in cool water and press small depressions in the center of the balls, then fill with warmed jelly.
Bake on the center rack of a preheated oven at 180°C (approximately 350°F), for approximately 10 minutes, until lightly browned. Remove from the oven and let cool. Sprinkle with powdered sugar and serve.