Finely chop the shallots, celery, carrots, and garlic.
Cut the Brussels sprouts in half.
Heat a drizzle of olive oil in a saucepan over medium heat.
Gently cook the shallots, celery, carrots, and garlic for a few minutes until softened.
Add the oregano, tomato purée, and Brussels sprouts. Stir well to coat everything.
Pour in the passata and stock, then bring to a gentle boil.
Add the pasta and stir for the first few minutes to stop it sticking to the bottom of the pan.
Cook for 10–15 minutes, until the pasta is tender and the Brussels sprouts are cooked through.
Taste and adjust with salt and pepper if needed.
Ladle into bowls and scatter over fresh herbs. Serve with a little grated Parmesan, if liked.