This vegetarian pasta dish is packed full of heartiness with sweet chard, umami mushrooms, and luscious fresh mozzarella. It'll be better than anything you can get at your local Italian trattoria!
Bring a saucepan of water to boil. Salt generously and add pasta. Cook until al dente, tender but not soggy. Save 1 cup (235 mL) of starch pasta water before draining.
Heat a saute pan over medium heat. Add walnuts and toast until golden and aromatic, 4 to 6 minutes. Remove from pan and set aside.
Return pan to medium-high heat. Add cooking oil and then garlic, shallots, and chard stems to heated oil with a sprinkle of salt. Saute until stems start to soften, ~3 minutes.
Add mushrooms with oregano and saute for another 3 minutes and then pour in crushed tomatoes. Simmer for 6 to 8 minutes.