In a large saucepan, combine onions, vinegar, water, salt, sugar and spices. Bring to boiling, reduce heat and simmer 5 minutes. Add beets and cook until heated. Remove cinnamon sticks.
Pack hot beets into hot jars, leaving 1/4 inch (6mm) head space. Pour hot pickling solution over beets, leaving 1/4 inch (6mm) head space. Remove air bubbles by sliding a non-metal spatula down inside the jar in several places.
Adjust caps and process 30 minutes in boiling water bath. This is for pints.