Preheat the oven to 180°C.
Cut the cauliflower and fennel into chunks and arrange them in a baking dish.
Cut the onion in half and tuck between the veggies together with the garlic. (No need to peel them).
Scatter the caraway seeds on top, then spray with olive oil.
Bake in the oven for 20-25 minutes, or until tender.
Transfer everything into a saucepan, then add the stock and bring to a boil.
Gently simmer for 10 minutes, then blend it in a liquidizer or with a hand-held blender.
Serve with a spoonful of cider vinegar or a dollop of crème fraîche.