Make the meatballs by combining the grated onion, nutritional yeast, salt, garlic powder, flour, and turkey in a medium bowl. Stir until well combined, being careful not to over-mix. Form into meatballs, about 1 teaspoon each.
Heat 1 tablespoon olive oil in an electric pressure cooker set to saute for 8 minutes. Add the onion and pinch of salt and cook until soft.
Add the carrots, celery, zucchini, diced tomatoes, chicken stock, Italian seasoning, salt and meatballs.
Secure the lid, select the manual setting, and set it to high pressure for 10 minutes. When the pressure cooker timer is done, quick release the pressure.
Uncover, add the spinach and stir until the spinach is wilted. Add the lemon juice, stirring to combine. Taste and add additional salt if desired.
Serve with a sprinkle of fresh rosemary and healthy drizzle of olive oil.