Prepare the stock, pouring the water, onion, carrot and bay leaf into a saucepan. Add some coarse salt and bring to the boil; cook for 30 minutes. For the fondue, cut the Taleggio cheese
into pieces and place in a bain-marie together with the milk and vegetable stock. Mix together until the cheese has completely melted.
In a small pan, cook the sugar with a spoonful of water and the apple vinegar; when it begins to caramelise, add the warm, reduced wine. Continue to cook until you get a syrupy sauce. In a large saucepan, sauté the onion with two spoonfuls of oil, add the rice and toast it for a few minutes. Add the hot stock a little at a time, cook the rice and season to taste.
When cooked, stir the fondue into the risotto and serve, pouring over 2 tablespoons of wine reduction.