Add mushrooms, carrots, onion, garlic and walnuts to a food processor and blitz to resemble a coarse mince texture.
Add oil to a wide-based pan over med heat. Tip in veggie mix along with oregano and a good pinch of salt and pepper. Sauté for 5 minutes to soften, scraping any sticky bits at the bottom of the pan with a wooden spatula.
Stir in tomato paste and vinegar and cook for another 5 minutes. This helps develop the umami flavour in the tomato paste.
Pour in crushed tomato then half fill the can with water, give it a swish and pour the water into the pan. Bring to a simmer, cover pan with a lid and cook for 10 minutes over low heat.
Meanwhile, cook your spaghetti in a pot of salted boiling water according to pack instructions. When the spaghetti is ready, drag the pasta into the bolognese sauce using tongs, taking along some starchy pasta water to create a silky sauce. Toss to combine and garnish with extra cracked pepper and basil to serve.
