Drain the stew while collecting the stock. Wash the mint, shake dry and chop except for a few leaves. Mix with yoghurt. Season to taste with salt and pepper.
Wash parsley, shake dry, chop. Peel onion and garlic and chop finely. Cut the chilli lengthwise, remove seeds, wash and chop. Puree drained lentil vegetables, half onion, garlic, chilli and parsley with a hand blender.
Knead in the flour. Season to taste with salt, pepper and about 1/2 tsp. cumin.
Cut out the lentil mixture with two moistened tablespoons of falafel balls. If the mixture is too soft, knead in a little more flour. Heat the frying oil to approx. 180°C in a deep fryer or a high pan.
Fry the falafel for 3-4 minutes in portions until golden brown. Lift it out and let it drip off on kitchen paper.
Meanwhile wash and halve the tomatoes. Heat olive oil. Brown the remaining onion and tomatoes. Deglaze with the lentil stock and vinegar, bring to the boil and simmer for 5-6 minutes. Season to taste with salt and pepper.
Do everything. Pita bread's good with that.