Prep: Preheat the oven to 400°F (200°C). Place the onions, garlic, celery, Jerusalem artichokes and fennel wedges on a rimmed baking sheet. Add the thyme leaves, oil, salt and pepper and carefully toss.
Bake: Bake in the preheated oven for 20 minutes. Carefully remove the sheet from the oven and pour the wine over the vegetables. Using oven gloves, gently shake the pan to spread the wine. Return to the oven for another 5-10 minutes, or until the vegetables are tender and the wine has almost completely evaporated. Remove from the oven and immediately stir in the beans.
Finish: Top with radicchio, hazelnuts, fresh thyme and lemon juice and serve either hot or warm. It's also delicious eaten at room temperature with a bit of vinegar like a salad.