2 tablespoons extra-virgin olive oil, divided
1 pound ground beef
1 pound bulk Italian sausage (hot or sweet)
1 onion, diced
2 garlic cloves, minced
1 (28-ounce) can pureed tomatoes
2 tablespoons tomato paste
1 tablespoon dried oregano
1½ teaspoons kosher salt
¼ teaspoon freshly ground black pepper
1 whole spaghetti squash (about 2 pounds), halved crosswise and seeds scooped out
¼ cup freshly grated Parmesan cheese
Heat 2 tablespoons of oil in the pot using the sauté function.
Add the beef and sausage and cook, stirring occasionally, until the meat is browned, about 5 minutes.
Add the onion, garlic, tomato puree, tomato paste, oregano, salt and pepper. Stir to mix well.
Close the pot, and turn the valve to the sealing position. Cook on high pressure for 25 minutes.
When the cooking time is up, quick release the pressure, and carefully remove the lid.
Give the sauce a good stir. Place the trivet in the pot on top of the sauce, and then place the squash halves, cut side up, on top of the trivet.
Close the pot again, and turn the valve to the sealing position. Cook on high pressure for 15 more minutes.
When the cooking time is up, quick release the pressure, and carefully remove the lid.
Remove the squash from the pot, and scrape out the noodle strands with a fork into a bowl.
Remove the trivet from the pot, and ladle the sauce over the squash noodles.
Serve immediately, garnished with Parmesan cheese.