In a dutch oven over medium heat, warm the vegetable oil, olive oil, and butter until melted. Add the white and green onions and sauté until soft. Add the salt and pepper and Herbs de Provence. Add the tomatoes by hand-squeezing the whole tomatoes into the dutch oven so they fall into pieces and release their juices. Add the carrots, celery, yellow pepper, red pepper, and potatoes. Stir well to combine all vegetables. Cover and simmer on low for 20 minutes, stirring occasionally.