Serve with Le Cirque chef Craig Hopson's Braised Short Ribs.
Place sunchokes in a large saucepan. Add milk and enough water to cover. Season with salt and bring to a boil over medium-high heat; immediately reduce heat to a simmer and cook until sunchokes are tender, about 30 minutes.
Drain, reserving cooking liquid. Return sunchokes to saucepan and add olive oil; mash with a potato masher until smooth. Stir in some of the reserved cooking liquid to moisten. Serve immediately.