Heat the oil in a saucepan and add the onion and garlic. Heat for 5 minutes to soften.

Tip in the cauliflower and fennel and stir for 4-5 minutes to coat in the oil.

Pour in the vegetable stock, thyme and salt and bring to a boil.

Simmer for 15-20 minutes until the cauliflower and fennel is soft.

Remove from the heat and using a stick blender, process until the soup is smooth.

Divide between 4 bowls and add a swirl of yoghurt and a sprinkling of extra thyme if you like.

This soup will keep in the fridge for 4-5 days.