1/ Fry the onions in a drizzle of oil, add the other ingredients. Reduce for 10 minutes. Keep to one side.
2/ Brown the duckling breast for 1 minute on each side in a hot pan with a drizzle of oil, then roast in the oven at 180°C for 6 minutes. Keep warm..
3/ Use the same pan to caramelise the walnuts and sugar for 30 seconds. Remove 12 leaves of the same size from the endive.
4/ Thinly slice the apple and cover in lemon juice.
5/ Thinly slice the duckling breast.
6/ Top each piece of toast with an endive leaf, a little onion chutney, one caramelised nut, a slice of apple and a slice of duckling.
7/ Garnish with chutney and caramelised walnuts.