Add all vegetables to a large bowl. Drizzle with olive oil and toss to coat.
Transfer the glazed vegetables to a parchment paper lined sheet pan, and season with salt and pepper. Then, place in the preheated oven on the second shelf from the top. Roast the vegetables for 25 minutes, until they're charred on the outside.
Melt butter in dutch oven over medium heat. Add onions and celery, cooking for four minutes. Add garlic and cook for one minute. Add flour and stir while cooking for another minute.
Add the vegetables to a large dutch oven, or heavy bottom stock pot, along with chicken stock, soy sauce, and diced tomatoes. Bring to a simmer over medium heat, cover and let them cook for 10 minutes.
Transfer the vegetables and liquid into a blender, and blend until smooth. Depending on the consistency you like, you may need to add some additional chicken stock.
Taste first, and then season with additional salt and pepper as desired. Garnish with sliced peppers or scallions and one tablespoon of heavy cream per bowl.