One pot pasta "bake"

Alright, it doesn't look amazing - but it was tasty, and rich and comforting.  I made it with GF pasta (red lentil fusilli), but obviously you don't have to.  I also think I put too much cheese in (particularly since I am lactose intolerant) but that just made it more luscious and gooey.

Onion
Olive oil
tuscan seasoning
red pepper
mushrooms
flagolet beans
pasta
water
passata
smoked german cheese (it gives a gentle smoky flavour and a silky richness)
emmental
grated cheddar
black pepper

1.  Sautee chopped onion and crushed garlic in olive oil.
2.  Add chopped pepper and mushrooms, sautee again for a couple of minutes.
3.  Add a tin of flagolet beans and a layer of pasta.  Pour in a carton of passata, and about a carton and a half of water.  Lid on, simmer.
4.  After about 10 minutes stir and then add chopped cheese, and allow to melt into the mmix.
5.  Serve, scoff ... blimey it was rich.