Preheat the oven to 350 degrees. Peel the onions and cut them into wedges about 1/2 inch thick at the widest part. Wash and dry the peppers. To cut a pepper, slice of the top and set aside. Remove the inside seeds and as much of the spongy core as possible. Slice the pepper in half and with a sharp knife. Remove the remainder of the spongy core so that all that is left is the deep colored pepper. Slice the half lengthwise into 3/4" wedges. Toss the olive oil, peppers, and onions in a bowl. Pour the contents into a jelly roll or sheet pan. Roast in the oven, tossing every 20 minutes for about 90 minutes or until very soft.
Nutritional information per serving: 230 calories, 15 g fat, 2 g saturated fat, 0 mg cholesterol, 10 mg sodium, 23 g carbohydrates, 6 g fiber, 3 g protein.