For the soup, heat the oil in a pan and gently fry the onion, garlic and leek for about 3-4 minutes, or until softened. Add the stock and simmer for 4-5 minutes, then stir in the cream. Season, to taste, with salt and freshly ground black pepper then blend until smooth with a stick blender.
For the croûtes, arrange the slices of bread on a tray and bake in the oven for 2-3 minutes, or until crisp. Remove from the oven, sprinkle over the cheese and chilli and return to the oven for a further 3-4 minutes, or until the cheese is melted.
Serve the soup in a bowl with the croûtes on the side.