I adapted this recipe from a Mediterranean cookbook years ago. This soup is a crowd pleaser, even for those who don't like lentils! It's a perfect pair with grilled flatbread and side salad for lunch, a starter before a hearty meal, or at holiday time...in shot glasses as a passed hors d'oeuvres. Regardless of how you serve it, there's never any leftovers! —cfgrlfrdy
Rinse lentils under cold water and put aside. Heat olive oil in a large heavy-bottom pot (I use Le Creuset) and cook the onion over medium heat until translucent. Add cumin and lentils to onions and toss to combine. Add chicken stock and bring to a boil over medium-high heat. Turn heat to low and simmer, covered, for 30 minutes until the lentils are very soft. Turn off heat and cool slightly.
Blend the soup in a traditional blender in batches and transfer to a bowl or a pitcher (I pour soup into an 8-cup Pyrex measure, then use an immersion blender to puree).
In the same pot (no need to wash it), make a roux...melt the butter, add the flour, stir to combine and cook over medium heat until roux is golden. Whisk in the pureed soup, and simmer for 5 minutes over low heat. Remove from heat.
In a small bowl or glass measuring cup, whisk together the milk and the egg yolks. Using a ladle, whisk a small amount of the hot soup into the milk and yolks and whisk to combine. Whisk mixture back to soup. Turn heat back on to low if needed. From this point, don't let soup boil as the eggs will curdle. Season with salt and pepper.
Variations: For vegetarians, this soup is equally as good made with vegetable stock. For a little heat, I like to add a couple of tiny dried piri-piri chilies to the onions when they're cooking. I also like to put homemade creme fraiche in a squirt bottle and decorate the top of the soup as I serve it. Serve with grilled or toasted flatbread, brushed with a good olive oil and sprinkled with sea salt. Enjoy!