Creamy Red Lentil Soup

1. For the croutons, cut the bread into 1 cm (1/2 inch) cubes. Heat the butter foams, add the bread and cook over medium heat until golden and crisp.drain on crumpled paper towels.
2. In a small frying pan, dry roast the cumin seeds until they start to pop and and become aromatic. Leave to cool, then grind to a fine powder in a mortar and pestle.
3. Rinse the lentils under cold water, then drain.
4. Melt half the butter in a heavy-based saucepan and cook the onion over medium heat for 5-6 minutes, until softened. Add the lentils, cumin and stock and bring to the boil. Cover and simmer for 30-35 minutes, until the lentils are very soft. Leave to cool, then puree in batches in a blender and transfer to a jug or bowl.
5. In a large heavy-based saucepan, melt the remaining butter over low heat. Stir in the flour and cook for 2-3 minutes, or until pale and foaming. Stirring constantly, add the lentil puree gradually, then simmer for 4-5 minutes.
6. In a small bowl, combine the egg yolks and the milk. Whisk a small amount of the soup into the egg mixture and then return it all to the soup, stirring constantly. Be careful not to boil the soup or the egg will curdle. Season with salt and pepper, to taste. Heat the soup to just under boiling and serve with the croutons.