Cut the celery, onion and carrots in small cubes. And cut the garlic in slices.
Use a food processor with a blade to cut the mushrooms very small. If you don't have a foodprocessor, you can just slice the mushrooms very fine by hand.
The Bolognese Sauce
Heat the olive oil in a baking pan, and add the onion, garlic, celery and carrot cubes.
When the onion turns glassy, add the mushrooms, thyme and bay leaves.
Bake for 5 minutes or until the mushrooms are brown. Then add the flour and keep stirring to make sure the flour doesn't burn on the bottom of the pan.
After 5 minutes, add the red wine and let the mixture cook for another 5 minutes.
Then add the stock and passata, and let the sauce cook for 1 hour on a low heat.
Bechamel Sauce
In the meantime you can make the bechamelsauce! Melt the butter in the cooking pan and add the flour. Mix and bake this until it smells like freshly bakes cookies.
Then add salt, pepper and the milk. Use a whisk to mix everything and to remove any lumps.
Preheat the oven on 390 degrees Fahrenheit or 200 degrees Celsius.
The Lasagne
Add some bolognese sauce to the oven dish. Top with a layer of pasta sheets. Repeat these steps until you are out of sauce or pasta sheets ;)
Cut the cherry tomatoes in half and tear the mozzarella in smaller pieces.
Top with the bechamelsauce, torn mozzarella, cherry tomatoes and some chili flakes. Bake the lasagna for about 45/50 minutes in the preheated oven. Top with basil just before serving!