Peel and finely dice the onion and garlic. Wash basil, shake dry, remove leaves and cut into strips. Heat 2 tablespoons of oil in a saucepan and fry the minced meat for 5-6 minutes, turning it well.
Add the onion and garlic, stir in the tomato paste and cook for 4-5 minutes. Season with salt and pepper. Dust with flour and sauté briefly. Add stock, tomatoes and oregano. Bring to the boil while stirring, using a spatula to roughly chop the tomatoes.
Simmer the sauce for about 5 minutes, stirring occasionally. Season to taste with salt and pepper, stir in basil, set aside.
Wash, clean and slice the aubergines lengthwise. Heat 3 tablespoons of oil in portions in a large frying pan. Fry the aubergines in portions for about 3 minutes, turning them over, and season with salt and pepper.
Grease an ovenproof dish (approx. 5 x 16 x 25 cm). Divide the minced sauce into 4 portions. Spread 1/3 of one portion thinly on the bottom of the dish. Cover with 4 lasagne plates. Spread 1 portion of chopped sauce on top, place about 3 eggplant slices on top and add another 1/3 of the chopped sauce from the opened portion.
Place 4 lasagne plates on top, spread 1 portion of sauce on top, place about 3 slices of aubergine on top and pour the rest of the opened portion on top. Cover with 4 lasagne sheets, spread the remaining portion of chopped sauce evenly and cover with the remaining aubergine slices.
Roughly grind the mozzarella and spread on the lasagne. Bake the lasagne in a preheated oven on the 2nd rack from below (electric oven: 200 °C/ convection oven: 175 °C/ gas: see manufacturer) for approx. 1 hour until golden brown.
Finely grate the parmesan. Remove the mould from the oven, sprinkle lasagne with pesto if necessary. Sprinkle with parmesan.