Place 1/2 lb ground beef in a medium bowl. Add 1/3 cup of rice, 1 egg, 1 tsp of salt.
Cut the 1 onion in half, chop one half of it and add the chopped part into the meat mixture. Mix everything well by hand. Round 1 inch wide meatballs from this mixture and set aside until needed. You can also perform this step right before adding meat into the pot.
Slice 1 tomato, slice 1 carrot, chop the rest of the 1/2 onion, cube 1 potato and set aside until needed.
Heat up your pressure cooker or your Instant Pot. In Insta Pot you would use saute function, add 1 TBSP of the oil of your choice and wait until the butter melts. One thing with Instant Pot is that it may take a little longer to brown ingredients. Once the butter is melted, add the chopped onions, and saute until transparent and slightly cooked. Add the sliced tomatoes and saute for about 5 minutes. Add carrots and cubed potatoes to the Pot and saute for another 3-5 minutes.
Add 2 tsp of salt, pepper, cumin, oregano, bay leaf and chopped garlic. Saute for 2 minutes. Pour 6 cups of water or the vegetable broth. You do not have to bring the water to boil with a pressure cooker method of making this soup.
Add meatballs into the water and close the lid of the pot. If you are using a regular pressure cooker, you will need to time it yourself. Ideally, timing should start from the time the lid is sealed and the hear a slight hiss incoming from the lid. You will also notice that the pressure button will come up. The beauty of Instant Pot is that it will do the job for you. It will only count time once the pressure is built and the lid is sealed. You can press the soup setting on the Instant Pot and modify the time. However, I like using the MANUAL setting for this soup. I press the MANUAL on the dashboard, select LOW pressure and set the time to 12 minutes. Once the time is up, let the steam out of the pot. Check the soup for the taste. Add salt if it needs any and your soup is ready to serve! Garnish with the herbs of your choice and voila!