Step 1

For the sauce: Add the oil to a 6-quart Instant Pot® and set to saute (see Cook's Note). Add the short ribs and brown well. Transfer to a plate, then add the pork ribs and brown well. Transfer to a plate. Add the onions and garlic and cook, stirring often, until the onions are golden and the garlic is soft, about 5 minutes. Add the tomato paste and stir well to coat all the onions. Pour in the wine and scrape up any browned bits on the bottom of the pot. Bring to a boil and let cook until reduced by half, about 2 minutes.

Step 2

Stir in the tomatoes, then add the beef, pork, sausages, 1 tablespoon salt, several grinds of black pepper and a pinch of red pepper flakes if using.

Step 3

Follow the manufacturer's guide for locking the lid and preparing to cook. Set to pressure cook on manual high setting for 50 minutes.

Step 4

For the meatballs: Meanwhile, combine the sirloin, Parmesan, breadcrumbs, milk, parsley, garlic, egg, some salt and a few grinds of pepper in a medium bowl and mix well with a wooden spoon. Form into 1- to 2-inch balls.

Step 5

After the pressure cook cycle is complete, follow the manufacturer's guide for quick release and wait until the quick release cycle is complete. Be careful of any remaining steam and unlock and remove the lid.

Step 6

Carefully remove the beef, pork and sausage. Skim any excess fat from the sauce and discard. When cool enough to handle, remove and discard any bones and excess fat from the meat. Chop the meat and sausage into bite-size pieces. Return the meat to the sauce and add the meatballs to the pot. Seal the pot and cook at manual high pressure for 5 minutes.

Step 7

After the pressure cook cycle is complete, follow the manufacturer's guide for quick release and wait until the quick release cycle is complete. Be careful of any remaining steam and unlock and remove the lid. Season with salt and pepper. Serve over pasta or polenta.