Peel the sunchokes. They are a pain to peel, but that’s about the most challenging part of this recipe! Cut them up in pieces.
Peel and dice the shallot (don’t cry, it’s ok!) Put the diced shallot in a dutch oven with the olive oil on low to medium heat, let it “sweat” without browning.
Add the sunchokes and add enough water to cover them. Add a pinch of salt. Bring to a boil, cover, lower the temperature and simmer for about 45 mn, until the sunchokes are soft (check them with a knife like you would a boiled potato).
Put the whole thing in a blender and mix. You can let cool and refrigerate for later, or serve right away.
When serving, reheat if needed and add the yogurt, and truffle oil if desired.