Peel and dice the onions and garlic.
Heat some oil in a large pan. Add the diced onions and let fry them gently for 5-10 min. Add the garlic and continue sweating the onions for another 3-4 min.
In the meantime prepare the cauliflower; cut into small florets. Then place on top of the onions with the thyme. Add the milk and vegetable stock and leave to simmer for 20min.
Once the cauliflower is soft, add the grated cheeses and blitz into a smooth soup. Add the mustard, chilli, Sherry and Worcestershire sauce and season with some salt and pepper.
Croutons
Melt butter in a frying pan, add the sliced garlic and thyme. In the meantime, dice the bread, then add to the pan and fry until golden and crisp. At the end sprinkle the parmesan of the croutons and give the croutons a good stir so that the cheese sticks to them.
Serve the soup with the croutons on top. Sprinkle with some fresh thyme leaves, a drizzle of olive oil and some fresh cracked black pepper.