Add the olive oil to the instant pot and set to saute. When the oil is hot add the sausages and roughly brown.
Add the onion and fry for a couple of minutes (deglaze the pot if necessary).
Now add the garlic, pepper and carrot followed by the dried herbs.
Season to taste and then add the wine if using. Cook for a couple of minutes to allow the alcohol to evaporate.
Add the Worcester sauce, tinned tomatoes, tomato puree, pasta and stock. Stir well together and deglaze the pot again if required.
Put the lid on and set to high pressure for 4 minutes.
Leave under pressure for another 4 minutes and then do a quick release.
Remove the lid and stir in the mozzarella.
Serve and enjoy.