Preheat oven to 275ºF
Place the tomatoes and onions on a half sheet pan and cover with a generous amount of olive oil, salt, pepper, garlic powder, and Italian seasoning.
Roast for 2-3 hours (this can be done in advance...I like to prep this after lunch and just throw it in the oven before we head out for afternoon activities!
About 20 minutes before you want to eat, heat a lidded pan to medium low, add the chicken broth and chicken, cover, and let slowly reheat.
To serve, layer the pasta, chicken, roasted tomatoes/onions, and then top with a splash of vinaigrette dressing and some parmesan cheese.