Turn the pot on to the Sauté setting. Add the ground beef and the onions. Cook, stirring occasionally, until the meat is cooked. Don't break up the meat completely, as some bigger chunks are nice in the soup.
Add the chopped carrots and potatoes, beef broth, onion soup mix, bay leaf, Italian seasoning, garlic powder, salt, pepper, and Worcestershire sauce. Stir.
Dump the can of diced tomatoes and tomato paste on top and do not stir.
Close the lid and set the steam release knob to the Sealing position.
Cancel the Sauté setting. Press the Pressure Cook/Manual button and set for 7 minutes. Make sure it is set to High pressure. It will take several minutes to come to pressure.
When the cooking cycle is finished, allow 15 minute natural release. Then carefully, in short bursts at first, release the remaining steam manually, by turning the steam release knob to the Venting position.
Stir the soup well to incorporate the tomato paste.
Then stir in the frozen vegetables and let sit for a few minutes before serving. The veggies will cook in the heat of the hot soup.
Serve hot with some nice crusty bread!