Eviscerate, scale, fillet (optional), wash and dry the fish.
Flour the fish, fry it in a non-stick pan, and salt it.
When the fish is golden and well cooked, lay it in a baking dish.
Cut the vegetables and sauté with a little oil and the wild thyme for 10 minutes.
Bring the wine and the vinegar to the boil, with the sugar, and then pour over the fish and the vegetables.
Leave to cool and put in the fridge.
The ideal would be to leave it for a few days (at least 24 hours), so that all the small bones that could still be in the fish can dissolve with the vinegar.
This recipe has been kindly provided by The Specialità Lariane, Tremezzina, Località Lenno