The Instant Pot is perfect for meatballs, allowing you to get a flavorful sear on the outside and then a quick pressure cooking cycle to cook them through to tender flavorful perfection!
Combine milk and breadcrumbs in a small bowl and let sit for 5 to 10 minutes.
Meanwhile add the meats, grated onion and garlic to a large mixing bowl.
Add the breadcrumb mixture and the remaining ingredients, except the marinara sauce, to the mixing bowl and gently combine with your hands. Avoid overworking the meat. If time allows, chill the mixture for 1 hour to make it easier to work with when forming your meatballs.
Line a rimmed baking sheet with parchment paper or foil. Using your hands, form 1 to 1½ inch meatballs and place them on the prepared baking sheet.
Cooking the meatballs
Set the Instant Pot to saute and allow it to preheat. Add the olive oil and sear the meatballs, working in batches to avoid overcrowding the pot. Cook for around 2 minutes, stirring occasionally, until well browned on all sides. Transfer to a plate and repeat with the remaining meatballs. Turn off the pot.
Add the marinara sauce (see note) and meatballs to the pot then lock the lid. Cook on high pressure for 7 minutes. Allow a 5 minute natural release then vent any remaining steam.
Notes
Freezing - This recipe makes about 12 servings. To freeze place the baking sheet with the formed meatballs in the freezer until frozen through. Then transfer the meatballs to a resealable freezer bag and store for up to 3 months.Marinara Sauce - I typically serve 3-4 meatballs per person and recommend 1 jar of sauce marinara for every 4 servings (16 meatballs).