Sauté the beef and aromatics: Set your Instant Pot to Sauté mode. Add the onion, and let cook. Then add garlic for a minute. Now add ground beef, breaking up the meat as it cooks.
Build the flavor: Pour in the water + bouillon, diced tomatoes, whole peeled tomatoes (crush them a bit with your hands or spoon), ketchup, Worcestershire, brown sugar (if using), and Italian seasoning. Stir everything together and season with a little salt and pepper.
Cook: Lock the Instant Pot lid in place and cook on soup mode on high pressure for 10 minutes. Manual release pressure.
Add the pasta: Stir in the dry elbow macaroni, then lock the Instant Pot lid in place and cook on soup mode again for just 2 minutes. Yes — only 2! That’s the sweet spot for perfectly tender pasta without it going mushy.
Quick release + serve: As soon as the timer beeps, do a quick release of the pressure. Open the lid, give it all a good stir, and taste to adjust any seasonings. Ladle into bowls and serve hot.