Melt butter and cook onions and sugar slowly until golden, about 30-45 minutes.

Slice 1/3 of the mushrooms and finely chop the rest.

Add all mushrooms and sauté for 5 minutes.

Stir in flour until smooth.

Cook for 2 minutes, stirring constantly.

Pour in water and stir until smooth.

Add remaining ingredients and heat to boiling, stirring constantly.

Reduce heat and simmer uncovered 10 minutes.

As in most soups, it is even better the next day.