Amount  Measure       Ingredient -- Preparation Method
--------  ------------  --------------------------------
                        ----Tomato Sauce----
  8             ounces  Italian sausage links
     1/4           cup  olive oil
  1              large  Spanish onion (about 10 ozs) -- peeled and diced small
  4              large  cloves garlic  (about 1 oz) -- peeled and chopped fine
  1         tablespoon  kosher salt
  2          teaspoons  fresh ground black pepper
  2                     bay leaves
  2             sprigs  thyme
  1              ounce  chopped basil
     1/2         bunch  parsley stems -- chopped fine
     1/2           cup  Italian tomato paste
  2               cans  (28 ozs each) tomatoes in juice -- San Marzano tomatoes
                        ----Stuffed Shells----
  1              pound  large pasta shells for stuffing
  1 1/2    tablespoons  olive oil plus ¼ cup (divided)
  1             medium  onion (4 ozs) -- peeled and diced small
  4              large  cloves garlic -- peeled and chopped fine
  1              large  bunch Italian parsley leaves, picked
  3             ounces  basil leaves
  2             pounds  whole milk ricotta cheese -- drained 10 minutes in strainer
  2          teaspoons  kosher salt
     1/2      teaspoon  nutmeg
  1           teaspoon  freshly ground pepper
  2                     egg yolks
     1/4           cup  mascarpone cheese
  6             ounces  aged Asiago cheese -- grated
  6             ounces  whole milk mozzarella cheese -- grated
  2             ounces  Pecorino_Romano cheese -- grated

Tomato Sauce: Oven @ 350°F. Cook pasta. Set aside.
Heat oil in heavy-bottomed pot and brown sausages. Remove sausages and set aside.

Add onions to pan and sauté until lightly browned. Add garlic and seasonings and sauté 1 minute, then add 
tomato paste and sauté 2 minutes, stirring. Add tomatoes, stir and bring to a boil. Add reserved sausages, 
cover and simmer in oven for 30 minutes.

Remove bay leaves and thyme. Remove sausages and save for another use. Adjust seasonings and cool sauce.

Prepare sauce and cook pasta. Set aside. Place a small sauté pan over medium-high heat. When hot, add 1½ tablespoons 
oil and onions and sauté until translucent, about 2 minutes. Add garlic and cook 1 minute. Remove from pan and cool.

Place parsley and basil leaves in food processor and process 1 minute. scraping side, until chopped. Add cooled 
onion mixture and process 30 seconds. Add ricotta cheese, salt, nutmeg and pepper and process until mixed.

In separate bowl, combine egg yolks and mascarpone and mix with a whip until smooth. Add to ricotta mixture and 
process until combined. Adjust seasonings with salt and pepper.

Set pasta shells on a large breadboard or flat surface. Fill a pastry bag (fitted with a tip that has a ½ inch opening) 
with ricotta mixture and fill each shell about half full. Go back and fill each shell, using up any remaining sauce over 
shells.

Place half the tomato sauce over bottom of large non-reactive ovenproof casserole that is large enough to hold all 
shells in one layer. If you do not have a pan large enough, use two smaller pans. Place shells in even rows over 
sauce with the filled side up. Drizzle remaining sauce over shells.

Mix Asiago, mozzarella and Romano cheeses together and sprinkle evenly over shells. Drizzle remaining ¼ cup 
extra-virgin olive oil over top of filled shells.

Bake in preheated oven 30 to 40 minutes until bubbly hot and lightly golden. Makes 6 to 8 servings.