Without peeling them, divide them into 2 or 3, depending on their size.
Peel and crush the garlic. Mix olive oil, garlic, thyme, black pepper and salt in a bowl. Cool baking paper on a baking tray. Transfer the Jerusalem artichokes on top.
Pour the garlic and spicy olive oil you prepared over the Jerusalem artichokes. Mix with your hands. Bake in a preheated oven at 180 degrees for about 20-25 minutes. Serve hot.