An easy and economical lentil soup flavoured with cumin and finished with a refreshing squeeze of lemon.
Melt the butter or heat the oil in a saucepan over amedium heat. Add the onion and cook until starting to soften and brown, stirring often (10-12 minutes).
Add the garlic and cook for another 2 minutes.
Stir in the cumin and a good grind of pepper near the end.
Add the lentils (drain and rinse first if you soaked them) and stir so they're coated in the seasonings and fat.
Add the stock and the sprig of thyme if using. Stir and bring to a boil.
Turn the heat down, put a lid on and gently simmer until the lentils are very soft (15-20 minutes for soaked lentils, 20-30 minutes for unsoaked - see Recipe Notes)
Take the soup off the heat (if you added thyme sprigs, fish them out and discard) and puree until smooth using a stick blender.
Taste and season with salt and more pepper if needed.
Stir in the lemon juice.
Serve the soup scattered with the chopped parsley.
Soup can be made in advance, cooled and stored in the fridge for 2-3 days or can be frozen.
Soaking the lentils in boiling water from a kettle while you gather and prepare the rest of the ingredients will cut their cooking time.
The recipe makes a light soup: add a further 50 grams of lentils for a thicker soup.