Rinse lenses cold, drain. Peel onion and garlic and dice finely. Heat 1 tablespoon of oil in a pot, fry the onion and garlic until transparent. Stir-fry the lentils for about 1 minute. Deglaze with 100 ml water. Stir in tomatoes. Cook over low heat for about 10 minutes until firm to the bite. Season to taste with salt, pepper and a little cinnamon.
Wash and clean the aubergine and cut it lengthwise into slices of approx. 1⁄2 cm thick. Heat 1-2 tablespoons of oil in a frying pan, fry the aubergine in portions on each side for about 1 minute.
Peel and wash the potatoes and cut them into slices of approx. 1⁄2 cm thickness. Approx. 2⁄3 Puree feta, crème fraîche and 75 ml water, salt and pepper.
Preheat the oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer). Place the lentils in a small casserole dish (approx. 15 x 20 cm). Place aubergine and potato slices alternately on top at a slight angle. Pour the feta cream on top. Crumble the rest of the feta and sprinkle over it. Cook in a hot oven for about 40 minutes.