Put some oil, mushrooms and spices you want !
Add beef meat
Let the preparation reduce
Meantime, boil pasta
Pre heat the oven. I can't tell you how long because my oven is kinda weird....
Put the meat mixture in an oven plate and alternate with pasta
Then mix with the bechamel sauce
Then cover with the grated cheese, then breadcrumb and if you want some butter (not so light...)
You can now put all this stuff in your hot oven for maybe 20'. Depends on your oven. Remember mine is a freako one !