Preheat the oven to 100°C.
To make the ragu: In a large ovenproof saucepan over a medium to low heat, gently fry the leeks, carrots and garlic in the olive oil until softened (but not coloured).
Add the tomato passata, fresh herbs, silverside and red wine and season to taste. Place the lid on the saucepan and secure tightly. Roast for at least 8 hours.
To make the pasta: In a large bowl, gently mix the flour and eggs using a fork until roughly combined. Transfer to a clean surface and knead with your hands until the dough comes together and has a paste-like texture.
Wrap in clingfilm and allow to stand at room temperature for an hour. Remove from the plastic and, using a rolling pin, roll out very thinly on a floured surface, then cut into long strips, each 2–3 cm wide (alternately, feed through a pasta machine).
Cook in a saucepan of salted boiling water for 2 minutes, or until al dente. Drain.
To serve: Ladle the hot pasta into bowls and top with generous spoonfuls of the sticky ragu and a scattering of grated Parmesan. Season to taste and serve.
Cook’s note: To make your own passata, cook 3 kg of ripe tomatoes in boiling water for 10 minutes. Drain, then strain the tomatoes in a vegetable mill or through a sieve. Heat a drizzle of olive oil in a saucepan, add the tomatoes and 4 cloves of chopped garlic and simmer for 10 minutes until reduced. Add a little sugar and a scattering of chopped basil and season to taste. For best results, slow-cook the beef ragu in the oven overnight.