Reverse-Engineering Trader Joe's Garden Vegetable Soup
I would sweat one of each of the vegetables (chopped) in 4tsp oil, beginning with the onion, leek, carrot, celery, and 2 sliced garlic cloves.  Then add a TBS of tomato paste. Add zucchini and sweet potato, one each, chopped, Cook for a minute or two.  Add 1/4 tsp black pepper and red pepper.  Add 1/2 tsp thyme.  Toss in one roasted red pepper, chopped, along with a 14 oz can  of chopped tomato.  Add 12 cups veg. broth and bring to a simmer.  Toss in a couple of cups of chopped mixed greens.  Cook until potato is done. Salt to taste.