Spaghetti Caruso - Lidia

Ingredients

• 1 teaspoon kosher salt, plus more for the pot
• 3 tablespoons extra-virgin olive oil
• 1 medium onion, sliced
• 8 ounces mixed mushrooms, sliced (button, cremini, shiitake, chanterelle, oyster)
• 8 ounces chicken livers, trimmed of fat and sinew, chopped into ½-inch pieces
• Pinch of crushed red pepper flakes
• 1 cup canned whole Italian plum tomatoes, preferably San Marzano, run through a food mill
• 1 cup frozen peas
• 1 pound spaghetti
• 2 tablespoons chopped fresh Italian parsley
• 1 cup freshly grated Grana Padano