Heat 1 tbsp olive oil in a large saucepan over medium-high heat, add beef and brown well, breaking up with a wooden spoon. While you’re doing this, blitz the silverbeet stalks, carrot, onion, celery and garlic in a food processor, then stir into beef along with herbs and spices. Add wine, bring to the boil and reduce by half (1-2 minutes), then add tomatoes and stock, bring to the simmer and cook for about 15 to 20 minutes until well-flavoured. Stir though silverbeet leaves and mushrooms in the last couple of minutes cooking along with vinegar.
Meanwhile, cook rigatoni in a large saucepan of generously salted boiling water until al dente, drain and toss through ragu. Serve hot scattered with parmesan and extra herbs and with crusty bread.
Mince with a higher fat content is best for this ragu, so avoid lean mince in this instance.