In a large bowl, add ground beef and top with salt, pepper, parmesan, garlic, onion powder, and oregano.

Mix the meat well with your hand or a hand mixer. Roll meat into balls. Place in the freeze for about 1 hour. These can be frozen larger but you will need to add more cook time if you freeze them longer. More information is in the post above.

Place trivet into the instant pot. Add one cup water. Place meatballs on trivet. Place the lid on top of the instant pot. Turn valve to sealed position. Set to high pressure for 13 minutes. Once the instant pot stops counting quick release the pressure. 

Remove meatballs and drain liquid. Place meatballs back into the pot without the trivet. Click saute and add the spaghetti sauce. Stirring the balls light around the sauce. It will heat up pretty fast. Once the sauce it heated turn off saute mode and set to keep warm. 

Cut the buns and then toast. Top with meatballs, parmesan cheese, and mozzarella