Cook onions, carrot, and celery
Add ground meat and let it cook slowly with tomato sauce
Melt butter in a small pot and add flour little by little
Slowly pour in warm milk while whisking until smooth and creamy
Start layering with a spoon of ragu
Add pasta sheets, white sauce, and sprinkle of parmesan
Repeat layers of sauce, pasta, and cheese
Top with mozzarella cheese
Bake until golden and bubbly
Let it rest before serving
Slice and serve
