Empty beets and their liquid into a small saucepan. Add onion, vinegar, water, sugar, salt, and pickling spice. Heat just until the sugar dissolves. Cool to room temperature. Pour the beet mixture over the eggs. Cover and marinate 2-3 days in the refrigerator before serving. Stir occasionally. To serve, spoon beets, eggs and some liquid into a serving bowl and top with a dollop of sour cream.