Essential ingredients: red split lentils, ground cumin, onion, dried mint, Turkish chilli flakes, oil, salt, pepper
Useful additions: stock, tomato paste, celery, carrot, easily wilted greens eg spinach/radish tops/chard
To finish: something to sour it - a squeeze of lemon or lime juice, a dollop of yoghurt, or a sprinkle of sumac all work well
Another one where the quantities vary - make it as thick or as thin as you like, add lots of vegetables or none but the essential onion.
Finely chop the onion and garlic and saute it until soft (also add finely chopped celery and carrot if you're using them). Stir in the tomato paste if you're using it, and cook for a couple of minutes, then add the ground cumin and stir until the scent is released. Add the red split lentils and cover with water or stock; add a teaspoonful of Turkish chilli and 3 - 4 teaspoonfuls or so of dried mint (not fresh, which has a very different flavour). Simmer until the lentils disintegrate: should take half an hour or so. If you like you can wilt some shredded greens into the soup at this stage.
Season with salt and black pepper, and finish with lemon/yoghurt/sumac and some more Turkish chilli flakes if you like.
Thanks to the Verbal Privilege blog (which is fascinating but not particularly about cooking) where I originally found a
version of this recipe.