Combine the ground beef, rice, bread crumbs, Parmesan cheese, parsley, garlic powder, salt, pepper, and egg in a large bowl and mix together until evenly blended.
Form the mixture into 1-inch meatballs.
Add the diced tomatoes, tomato paste, and water to the Instant Pot and stir to combine.
Add the meatballs to the pot, making sure they are submerged in the sauce.
Secure the lid and set the pressure valve to sealing. Select the “manual” or "high pressure" setting and set the timer for 10 minutes.
When finished cooking, release the pressure naturally for 10 minutes, then quick-release the remaining pressure.
Serve the meatballs with the tomato sauce over hot cooked rice or pasta.
Interesting Facts
Porcupine meatballs are a classic Italian-American dish that is traditionally made with ground beef and white rice.
The name "porcupine meatballs" comes from the fact that the meatballs look like porcupines when they are cooked in the tomato sauce.
The Instant Pot makes this recipe quick and easy, and the pressure cooking method helps to seal in the flavor of the sauce and the juiciness of the meatballs.