Turn on oven to 400 degrees to preheat. Prepare spaghetti squash to be roasted by slicing into 1/2" rounds. Once they have been sliced into rounds remove the seeds and brush with 1 Tbsp of olive oil and salt a pepper. Be sure to coat both sides.
Place parchment paper or foil on a baking sheet and lay out the spaghetti squash in an even layer. Place in the oven to roast for 45 minutes.
While the spaghetti squash has began roasting chop and slice all of the remaining vegetables. Place in a bowl and toss with the remaining 2 Tbsp of olive oil and the Italian seasoning.
Once the spaghetti squash has roasted for 30 minutes remove from the oven and turn all of the slices. At this time place the remaining vegetables in the oven on a baking sheet also.
After an additional 15 minutes when all of the vegetables have cooked through remove them all from the oven. Make a slice in all of the spaghetti squash rings then using a fork separate the squash from the peel.
Using the spaghetti squash as the "pasta" plate it and place the roasted vegetables on top. Due to the water content in these vegetables I did not find it necessary to add more oil. If you feel they are too dry you may add more oil to your liking and toss the vegetables together. Serve warm and garnish with fresh basil if desired.
Feel free to replace the olive oil with another lightly flavored oil like avocado if desired.