Turn on pot to the Sauté setting. Add the olive oil, hamburger, pork, garlic and onion. Cook until the meat is cooked through.
Add spinach, black olives, sun-dried tomato and additional onions, salt and pepper to taste.
Stir the mixture scraping the bottom of the pot to deglaze (get up any browned bits).
Pour the tomato sauce over the mixture and cover it completely. Do not stir.
Cancel the Sauté function. Put the lid on the pot and turn the steam release knob to the Sealing position. Press the Pressure Cook (Manual) button or dial, and then the +/- button or dial to select 4 minutes.
When the cook cycle is finished, do a Quick Release of the pressure/steam by turning the steam release knob to the Venting position.
When the pin in the lid drops down, open the lid and stir the pasta. Stir in half of the cheese and 3/4 of the pepperoni.
Stir in olives, if using, or any other add-ins you’d like.
Sprinkle the remaining cheese on top and arrange the remaining pepperoni on top of the cheese. Close the lid and let the cheese melt.
Serve from the pot or transfer to a casserole serving dish.