Prepare the Bayonne ham chips:

1. Preheat the oven to 400°F (200°C).
2. Cut 1 slice of ham into 4 equal pieces.
3. Use parchment paper to cover the baking tray.
4. Put the 4 pieces of ham on it and cover with another sheet of parchment paper.
5. Place an empty baking dish to hold everything in place and to keep the ham from curling.
6. Bake in the oven for 10 minutes.

Prepare the caramelized onion slices:

1. Heat the olive oil in a frying pan on medium heat.
2. Add the onion and salt and cook for 2 minutes.
3. Add sugar and cook until the onion caramelizes (2-3 minutes).
4. Put aside.

For each tartine:

1. Add butter, arugula, a half slice of ham, cheese sticks, slices of mushroom, caramelized onion slices, 2 walnuts, 2 chives and 1 crispy ham chip to each tartine.
2. Drizzle a teaspoon of olive oil on top.
3. Add a half teaspoon of balsamic vinegar pearls on top.