Peel and finely chop the onion and garlic, and wash and finely chop the Brussels sprouts. Heat the olive oil in a pan then add the onion and fry for 1-2 minutes, until softened but not coloured.

Add the garlic and Brussels sprouts and pour in enough stock to just cover. Add the black pepper (if using). Bring to the boil then reduce the heat and simmer for 3-4 minutes, stirring occasionally until the sprouts are just tender. 

Blend the soup until smooth using a hand blender or food processor

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For the cheesy croutons, cut the ciabatta into small pieces. Heat the oil in a frying pan then add the ciabatta and fry for 4-5 minutes until the croutons are golden brown and crisp all over. Remove from the heat and crumble over the cheddar. Season with freshly ground black pepper to taste.

To serve, divide the soup between 3-4 bowls and top with the cheesy croutons.

This soup has a wonderfully rich flavour. If you prefer a slightly milder flavour then try adding a large, finely chopped potato with the sprouts (or a cooked potato at the end). You can also add a swirl of yogurt to the bowl just before serving to balance the flavour.