Prepare the Meatballs: In a large bowl, combine the ground beef, breadcrumbs, Parmesan cheese, egg, garlic, parsley, oregano, basil, salt, and pepper. Mix until just combined. Use your hands to form the mixture into 1-2 inch meatballs.
Set Up the Instant Pot: Add 1/2 cup of water to the Instant Pot’s inner pot. Place the trivet (the metal rack) inside the pot.
Sear the Meatballs (optional): If you want a crispy exterior, select the “Sauté” function on the Instant Pot. Once it’s hot, add the meatballs in batches, searing them on all sides for 2-3 minutes. You can skip this step if you prefer to cook the meatballs directly in the sauce.
Add the Sauce: Once the meatballs are browned (or if you skipped the searing), pour the marinara sauce over the meatballs in the Instant Pot.
Cook the Meatballs: Close the lid of the Instant Pot, ensuring the valve is set to “Sealing.” Select the “Pressure Cook” or “Manual” setting and cook on high for 8-10 minutes.
Release the Pressure: Once the cooking time is complete, let the pressure release naturally for 5 minutes, then switch the valve to “Venting” to release any remaining pressure.
Serve: Carefully open the lid, remove the meatballs, and serve them with pasta, rice, or on a sandwich bun. Enjoy!