Peel and chop the onions. Fry with the minced meat in hot oil for seven minutes. Season with salt and pepper. Add tomatoes, tomato paste and bay leaf. Let the sauce thicken while stirring occasionally. Season with salt, pepper, paprika and sugar.
Remove the bay leaf and put the minced meat sauce aside. Peel carrot, clean and wash zucchini. Cut both into small cubes. Melt the fat in a pot. Sauté the diced vegetables for three minutes. Add flour and sauté while stirring. Stir in stock, milk and cream bit by bit. Bring to the boil again and let it swell for five minutes at low heat. Season sauce with salt and pepper. Spread some of the béchamel sauce on the bottom of a rectangular casserole dish (30 x 25 cm). Spread six lasagne plates on top. Spread half of the minced meat sauce on top, add some béchamel sauce and cover with six lasagne dishes.
Bring to the boil again and let it swell for five minutes at low heat. Season sauce with salt and pepper. Spread some of the béchamel sauce on the bottom of a rectangular casserole dish (30 x 25 cm). Spread six lasagne plates on top. Spread half of the minced meat sauce on top, add some béchamel sauce and cover with six lasagne dishes. Spread the rest of the minced meat sauce and again some béchamel sauce on top. Cover with the remaining lasagne plates. Spread the rest of the béchamel sauce on top. Grate the cheese and sprinkle evenly over the lasagne. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 45 minutes. Wash parsley, dab dry and chop. Sprinkle over the lasagne
Cover with the remaining lasagne plates. Spread the rest of the béchamel sauce on top. Grate the cheese and sprinkle evenly over the lasagne. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for 45 minutes. Wash parsley, dab dry and chop. Sprinkle over the lasagne