Preheat the oven to 400 degrees F.
Wash the vegetables.
Remove a piece of the top and bottom of the vegetables. Clean out the seeds and membranes from the bell peppers.
Roughly chop all of the vegetables. You do not need to peel them.
Place all of the chopped vegetables into a large roasting pan.
Pour the olive oil over the vegetables and toss them with your hands to coat.
Lightly salt the veggies, toss again, and sprinkle with a little more salt.
Place the dish in the oven and let cook for one hour.
Remove the dish from the oven and stir the vegetables using a silicone spatula or large spoon. At this point, they will not have changed appearance that much.
Return to the oven and let cook for an additional 30 minutes.
Remove the dish from the oven and sprinkle with 3/4 tsp herbes de Provence. Stir and sprinkle with the rest of the herbs. Give the vegetables one more stir, being sure to come up from the bottom of the pan.
Return to the oven for 30 minutes, then remove and stir. At this point you are looking for the vegetable to be very soft and to have a "jammy" consistency. If this has not yet happened, return to the oven for about 30 minutes, checking regularly to be sure it does not burn. I needed an additional 30 minutes for a total cooking time of 2 1/2 hours.