Add the onion, garlic, zucchini, carrots, celery, sweet potato, garbanzo beans, quinoa, brown lentils, and vegetable broth to the Instant Pot. Stir well to combine.
Secure the lid and set the valve to Sealing.
Cook on High Pressure for 8 minutes.
When the cooking time is complete, carefully perform a quick release.
Remove the lid and stir the soup. Taste and season with salt and black pepper as needed.
Let the soup sit for 5 minutes before serving to allow it to thicken slightly.
Notes
The quinoa and lentils will naturally thicken the soup as it sits. Add a splash of broth when reheating if needed.
For extra flavor, stir in fresh minced parsley or cilantro before serving.
This soup stores well in the refrigerator for up to 4 days and freezes well.