My co-worker brought this in for lunch and let me sample it and I knew I had to try to make a batch.  Served it over Spaghetti noodles for Guy and Zoodles for me and both versions were very good.  It makes a ton and froze several servings.  Definitely on the list when we need a pasta sauce.Adapted from the Nom Nom Paleo recipe book "Ready or Not".Ingredients

• 1 tablespoon extra-virgin olive oil
• 3 pound sweet and/or hot Italian sausage
• 1 small yellow onion, diced
• 2 medium carrots, diced
• 2 celery stalks, diced
• Kosher salt
• 6 garlic cloves, minced
• 1/4 cup tomato paste
• 1/2 cup chicken stock
• 3 28-ounce cans whole San Marzano tomatoes
• 2 dried bay leaves
• 1 teaspoon dried oregano
• 1/2 teaspoon freshly ground black pepper
• 1/4 teaspoon red pepper flakes
• 1/2 cup chopped fresh basil
• 1/4 cup chopped fresh Italian parsley

InstructionsSaute all sausages for 3-4 minutes, remove from InstaPot and set aside. While you are doing this open and drain the San Marzano tomatoes then blend to fine puree and set aside.Saute Carrots, onions, celery with sprinkle of salt until all are softened, about 10 minutesAdd tomato paste to vegetables, stir and saute 2-3 minutes, Add chicken stock, bay leaf and seasonings. Stir well then add San Marzano tomato puree and stir well. Add whole sausages and "drown" in the sauce.Cook on InstaPot setting Manual, high for 50 minutes and then let natural release for 10 more minutes.  Remove sausages, cut or chop into small bite sized pieces, add back into sauce and let simmer until ready to eat.This makes a huge amount of sauce and it does freeze very well.