Add 1 tbsp olive oil in a large deep pan over medium-high heat, then place in half your mushrooms. Leave to brown on one side, then use tongs to flip them over and season with a pinch of salt and pepper. Continue frying until golden brown on the other side, then remove to a side bowl and repeat with the second batch, adding more oil as needed. Remove again once done. It's important not to cram in the mushrooms or they'll steam and lose flavour. Also important to not move them about too much or they won't brown properly.
Lower the pan to medium heat then add another drizzle of oil and add in onion. Fry until soft and just starting to pick up colour, then add in garlic and fry for another couple of mins. Add tomato paste (puree) and stir & fry for 1-2 more mins.
Add in chopped tomatoes and swill out the cans with around 1/2cup/120ml water. Add back in the mushrooms, then add in most of your parsley (save some to garnish), oregano, basil, chilli flakes and a good pinch of salt and pepper.
Give it all a good stir, then leave on a very gentle simmer for 35-40mins or until nice and thick. This is important to marry all the flavours together.
Just before the sauce is done, add your pasta to salted boiling water and cook until al dente. Reserve a cup of starchy pasta water before draining.
Stir pasta into the sauce, then stir in parmesan. If you need to loosen up the sauce add in a splash of starchy pasta water, if not just discard.
Serve with any extra parsley & parmesan then tuck in and enjoy!