Melt the butter in a thick bottomed stainless steel pot over a medium high heat but don’t allow it to burn.
Add the sliced onions and slowly fry to soften, once the onions drop continue to fry slowly browning, stirring and adding colour without burning. Continue until your onions reach a satisfactory colour.
Add the 4 table spoons of water to deglaze the bottom of the pan.
Add the flour and stir and cook briefly.
By the time your onions are well browned a full pot of onions will have reduced in volume as you can see in this image here.
Have your Chicken Stock standing by hot on the stove.
Add the chicken stock and the salt and pepper.
Add the sugar and white wine.
Stir and return to a simmer.
Taste with a spoon to check the seasoning, consider adding chicken powder if required.
Leave on a very slow simmer for another 10 minutes.