Peel and cut the onion and the garlic clove. Wash carrots and the celery stalks and chop them. Rinse red lentils with water in a finely woven strainer and crush the cilantro seeds in a mortar.
Heat 2 tsp of sesame oil in a pot. Soften onion and garlic cubes. Add the chopped carrot and celery stalks and roast it for 2-3 minutes.
Add the crushed cilantro seeds till it develops an aromatic smell. Then add red curry paste, the rinsed lentils and 850 ml (3.5 cups) water.
Bring it to a boil, then reduce heat and let the ingredients simmer for about 12 minutes, till the lentils and the veggies get soft.
Puree the soup with a hand blender (or in a blender) and season it with tumeric, cumin, garam masala, soy sauce (or salt) and lemon juice. Dilute the soup with water to your liking.
Let the soup cook/simmer for another 5 minutes and add two handful of washed baby spinach. If you like, also add some chopped cilantro.
Pour the soup into bowls and serve it hot garnished with vegan yoghurt, cilantro and sesame seeds (and some chili flakes, if you like)