Remove the leaves from the Brussels sprouts. This is the most time-consuming work, but it is worthwhile because the Brussels sprouts lose their bitter substances.
Finely dice the apple and bacon and pound the walnuts into small pieces. Let the sugar caramelize and fry the apple with the walnuts. Then deglaze with a dash of raspberry vinegar. Put the mixture, warm as it is, in a bowl.
Then fry the bacon and add to the apple mixture.
Sweat the Brussels sprouts in a pan with a dash of water. Add salt, pepper and a little broth and let it steep. Add to the bowl, sprinkle with parmesan and serve.