Peel and finely chop the onion, garlic and ginger. Heat butter in a large pot. Roast cumin, turmeric, chilli flakes and caraway in it for about 30 seconds while stirring. Add the minced meat and fry until very finely crumbly.
Season with salt. Fry onion, garlic, ginger and lentils briefly.
Add approx. 1 l water and bring to the boil. Cover and cook over medium heat for about 15 minutes until slightly creamy.
In the meantime, sort out the spinach, wash and drain. Stir into the lentil soup about 3 minutes before the end of the cooking time. Season to taste with lemon juice, approx. 1 tsp. salt and pepper if necessary. If you like, add the lentils cut into fine rings.