(No gluten, dairy; with options for vegans and no nightshades)
It doesn’t get much easier than this: basically, throw everything into a pot and simmer. The final addition of lemon and parsley beautifully refreshes, lifts the colour and provides punch. This has a richer flavour with chicken stock, but can be done vegan with top quality vegetable stock (try a little non-traditional flaky yeast or dark miso* for the umami flavour or savouriness that meat provides). The soup is heartier with soaked green lentils, but you could use red lentils which require no soaking. Adding salt after legumes are cooked helps them cook faster. A stick/immersion blender is easiest to use right in the saucepan.