Preheat oven to 400°F (200˚C) and spray a baking sheet with cooking spray.
Place red onion, tomatoes, orange bell pepper, and squash evenly on a baking tray.
In a small bowl, mix together melted butter, garlic powder, salt, pepper and Italian seasoning.
Brush half of the herb butter over the vegetables and push them to either side of the to make room for the steak. Place the steak in the middle of the pan. Brush both sides of the steak with the remaining herb butter.
Place back into the oven for 20-30 minutes or until desired doneness of the steak is reached. Using a meat thermometer, you will want to take the steak out when it reaches 130 degrees for rare, 140 degrees for medium rare, 155 degrees for medium, and 165 for well done (the steak will continue to cook while it rests).
Allow the steak to rest under aluminum foil for 5-10 minutes before slicing and serving with the vegetables.
This recipe serves 4 people. One serving is approximately 4 oz of cooked steak and about 1 cup of roasted vegetables.