Peel and wash the carrots and celery. Clean the leek, wash it thoroughly. Cut prepared vegetables into fine cubes. Peel and finely dice onion and garlic. Heat the oil and fry the minced meat for about 10 minutes, turning it well.
After 6 minutes add the vegetable cubes. Stir in tomato paste and dust with 1 tbsp. flour. Add 250 ml broth and tomatoes. Bring to the boil while stirring, chop the tomatoes coarsely. Dab anchovies dry, chop very finely and add to the sauce.
Season to taste with herbs, salt, pepper and sugar. Simmer the sauce for about 5 minutes while stirring. For the béchamel sauce melt the fat in a pot. Add 3 tablespoons of flour and sauté. Add 500 ml broth and milk while stirring.
Bring to the boil, simmer for 2-3 minutes while stirring. Season to taste with salt, pepper and nutmeg. Grease an ovenproof dish (approx. 30 x 20 x 5 cm). Spread some béchamel sauce thinly on the bottom of the dish. Place 4 lasagne plates on top.
Spread about 1/4 of the minced sauce on top. Put some béchamel sauce back on top and cover with 4 lasagne sheets. Repeat the process with 3 more layers of pasta. Spread the rest of the béchamel sauce on the last pasta layer.
Grate parmesan and cut mozzarella into slices. Spread the cheese on the lasagne. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for about 1 hour until golden brown. Arrange the lasagne.
Served with a salad seasoned with mint.