Preheat the oven to 450'.
Cut the cauliflower into florets and spread them on a rimmed baking sheet. Drizzle with olive oil, sprinkle the fresh nutmeg and a hefty pinch of salt and pepper and toss everything to coat.
Bake on the middle rack for about 35-45 minutes, tossing the cauliflower halfway through, until they are fully roasted and you see a good amount of brown edges.
Remove to cool.
While the cauliflower roasts, start the broth. Heat the oil in a saucepan and saute the shallots and garlic for about 5 minutes to soften. Add the vegetable broth, dried thyme and vinegar and warm through.
When the cauliflower is cool to touch, add it and the broth mixture to a food processor or blender and process until smooth. Taste for salt and pepper. If you want more contrast, add a bit more vinegar. Add it back to the saucepan to keep warm.
To make the croutons, heat the remaining oil in a small pan, add the torn bread and a pinch of ground pepper and stir it around for 5-8 minutes until crisp and the edges are browned.
Serve each portion with a few croutons, chopped hazelnuts and a pinch of fresh thyme leaves and shaved parmesan, if using.
