Clean, wash and finely dice the carrots and celery. Peel onion and cut into cubes. Remove the rind from the bacon and dice the bacon finely. Pour the tomatoes onto a sieve and collect the juice.
Roughly chop the tomatoes. Heat 2 tablespoons of olive oil in a frying pan and leave the bacon crispy. Remove the bacon and fry the minced meat in it. Braise the celery, carrot and onion briefly. Stir in tomato paste and add tomato juice.
Add bacon and tomatoes and season with salt, pepper and Italian herbs. Cook at medium heat for about 10 minutes. For the béchamel sauce, heat fat in a pot. Sweat flour in it and deglaze with broth, milk and cream.
Bring to the boil, add 100 g parmesan, stir in and season to taste with salt, pepper and nutmeg. Grease a large lasagne dish and spread 1/4 of the béchamel sauce on the bottom of the dish, cover with 3 lasagne sheets.
Spread half of the Bolognese on top. Spread 1/4 of the bechamel on the bolognese and cover with 3 lasagne plates. Repeat the next layer like this. Cover the top layer of lasagne with the remaining béchamel sauce.
Sprinkle with the remaining Parmesan cheese. Bake in the preheated oven (electric: 200°/ gas: level 3) for about 40 minutes until golden brown.