This is one condiment that I have made which I find extremely useful as a base for making gravy for all meats and I usually make a batch of this when I have a net of onions I am coming to an end of, waste not want not and all that jazz.
It is taken from The Victorian Kitchen Book of Pickles and Preserves ISBN 1 85833-460-8.
1/2 pint/300 ml Fresh Water
8oz/225g Moist Brown Sugar
1/2 pt/150ml Tarragon Vinegar
Peel and finely chop the onion; put in a saucepan and cover with the water. Bring to the boil and cook until the onion is soft then add the sugar and simmer until it has dissolved and turned the contents of the pan very dark brown.
In a separate pan boil the vinegar and very slowly stir this into the onion mixture. When it is all combined remove from the heat and allow to cool before bottling.
I use a teaspoon/2 teaspoons per batch of gravy
Result very tasty gravy