Heat a large pot over medium high heat. Add oil. Add diced onion and cook for about 8 minutes. Stir in garlic and cook for 1 minute. Stir in carrots, potatoes, and sweet potatoes. Sprinkle with salt and pepper. Cook for 1-2 minutes longer.
Stir in tomatoes and broth. Add corn, zucchini, green beans, thyme, parsley, basil, and red chili flakes. Reduce heat to low, cover, and heat for 25 minutes.
Check for seasonings. May want to add 1 teaspoon of salt or garlic salt. Sprinkle with freshly grated parmesan cheese.