Heat some more oil in a large pot over medium heat. Add the fideo pasta. Fry the pieces for 5–6 minutes or until they become crispy and golden brown in color. Leave the fideo in the pot, you’ll build the soup directly on top of it.
Next, combine the onion, garlic, cumin, oregano, diced tomatoes, tomato sauce, and beef broth in a blender. Then, pulverize the mixture until it's completely smooth and lump-free.
Add the blended tomato soup base to the pot containing the fideo. Heat the mixture over medium-high and cook the soup for about 10 minutes.
At this point, add 1–2 additional cups of beef broth or water if needed, depending on how soupy you prefer it.
Next, add the browned meatballs and continue cooking the soup for another 10-15 minutes.
Adjust the seasoning of the Sopa de Albondigas con Fideo by adding salt and pepper.
Before removing the soup from the heat, ensure that the meatballs are completely cooked through. They should reach an internal temperature of 160°F (71°C) for safe consumption.