Mario Pei’s Lasagne

Ingredients

• 3 tablespoons oil
• 1 medium yellow onion, peeled and chopped
• 4 cloves of garlic, minced
• 1 ½ pounds sweet Italian sausage, casings removed
• 1 tablespoon chopped fresh parsley
• 1 32 ounce can peeled Italian plum tomatoes
• 1 5 ounce can tomato paste
• Salt and pepper
• ½ teaspoons dried basil
• 1 pound fresh ricotta
• 1 egg, lightly beaten
• ½ cup parmigiano-reggiano
• 1 pound dried lasagna noodles
• 1 pound fresh mozzarella, thinly sliced