Curried cauliflower soup

Method

1. Chop the cauliflower into florets and finely chop the stalk. Heat the vegetable oil in a large saucepan over a medium heat and cook the chopped onion, chopped cauliflower stalk, garlic-ginger paste and curry powder for about 6 minutes. Add the potato, cauliflower florets and stock. Bring to the boil then turn down to low and gently simmer for 30 minutes.
2. Dice the slice of bread into 1cm cubes. Melt the butter in a small frying pan over a medium heat and add the croutons with a pinch of salt and the mustard seeds. Tip the frying pan so the bread is covered by the foaming butter and cook until you have golden, crisp croutons (about 4 minutes). Drain on kitchen paper.
3. When the soup is ready, add the créme fraîche (if using) and use a stick blender to whizz the mixture until smooth. Season with salt, pepper and lemon juice. Divide the soup between bowls with the croutons and mustard seeds sprinkled on top and the sandwich on the side.