Prepate the jam jars (cleaning...).
Trim the onions & cut them into quarters; afterwards cut the onions into thin slices. Start frying the onions in olive oil in a pot big enough for the jam session.
Add the spices - the juniper berries in the tea-ball - & fry softly until the onions are soft. Don't forget to stir the mess every now & then. It shouldn't stick to the bottom.
After about 30 min add red wine & vinegar - let it cook softly & stir for about 10 - 15 min. The liquid should have evaporated...
Remove the tea-egg!
Add the preserving sugar & bring it to a boil. Attention: when the sugar is dissolving the liquid will increase again!
Let it boil for at least 3 - 5 min - always stirring!
Then fill the onion mess into the jam jars - immediately - & close the screw cap. Turn the jam jars upside down for cooling.