Cut a piece of Brie cheese by half lengthwise (to cut it this way, the cheese must be cold, so put it in the fridge before cutting).
For the caramelized onion, julienne 2 or 3 onions and put in a pan with a dash of olive oil. Simmer to cook slowly. Add salt and pepper. Allow to cook as slowly as possible so the consistency is very soft. Once translucent, soft and dry, add 2 tablespoons of sugar and turn the heat up so it caramelizes. Once it turns into a nice caramel color, remove from the heat.
Place a layer of baby arugula in a plate, then one of the pieces of cheese, and add a generous layer of caramelized onion; then cover with the second piece of cheese. Decorate with walnuts and almonds. And add some rough bindweed fruit to make it extra Christmassy.