This lasagna is my own improvisation, which makes for a good alternative for when you don't have time to make various sauces and stuffings. First make the Bechamel sauce: put the butter in a pot on the stove, wait for it to melt and add the flour while stirring nonstop.
Wait 1-2 min. for the flour to braise lightly and pour in the milk. Stir energetically until the sauce thickens and season with salt and pepper. Remove from the heat. Cut the smoked pork neck into thin pieces, the processed cheese into round slices, the smoked gouda into medium thick slices.
Prepare a suitable rectangular tray, smear its bottom with a little Bechamel sauce, arrange sheets on it next to each other. I was able to place 3 1/2 sheets per row. On them, put pieces of smoked pork neck, distribute slices of the processed cheese, sprinkle with the tomato-mushroom sauce and cover with a thick layer of Bechamel sauce.
Make the 2nd layer by putting lasagna sheets on again, then smoked pork neck and finish off with strips of gouda. Pour tomato-mushroom sauce and Bechamel sauce on again. Make a 3rd and 4th layer the same way, alternating lasagna sheets, pork, processed cheese, sauces, then sheets, pork, gouda, sauces.
Finish the last layer off with sauce. All of the lasagna sheets need to soak in lots of sauce so that they soften during baking and the lasagna turns out juicy and not dry. Cover the tray with aluminum foil and place in a preheated 356°F (180 °C) oven for 45 min.
Grate the cheese, take the tray out, remove the foil and sprinkle the lasagna generously with the cheese. Return to the oven for 10 min. until it melts to a golden color. When serving, wait briefly for it to cool and then cut it.
Notes: I used spinach-flavored lasagna sheets but you can use plain. Tomato sauce with mushrooms is really good and saves a lot of time but you can make it yourself if you like.