For the lentil stew, bring water to a boil, add black lentils and simmer for 30 minutes.
Meanwhile, peel potatoes and garlic, grate finely and add to lentils. Add turmeric, cumin and tomato paste.
When there are 15 minutes left of the cooking time, add red lentils and finish cooking. Stir in soup powder and season with salt, pepper and lemon juice.
Cut feta into cubes and fry in hot olive oil until brown. Serve lentil stew with fried feta and chopped parsley.
Crispy baked pita bread is delicious with the lentil stew.