Heat olive oil over medium heat.
Add onions, salt and pepper and cook for about 5 minutes.
Add garlic, celery and carrots and cook for another 5 minutes. They should be slightly soft. Add tomato paste and cook for one minute longer.
Add the rest of the ingredients, holding back 1 cup of the vegetable broth and the spinach. Bring to a boil. Turn back heat to simmer, cover and simmer for about 20 minutes. Stir occasionally to ensure pasta doesn't stick to the bottom of the pot. Taste the pasta and vegetables to ensure they are soft. If not, simmer for about another 5 minutes. Taste and adjust seasoning. If you overcook the soup, the pasta will overcook.
Add the spinach and heat until wilted (a couple of minutes). If your soup is thick, add the additional cup of vegetable broth. Keep in mind, this soup will also thicken up when left over.
Optional: Serve with some vegan parmesan on top!