Preheat oven to 400 degrees. Arrange the vegetables in a single layer on a baking sheet, season with salt and pepper and spray with cooking spray. Roast until tender and browned about 30 minutes. Remove from oven and set aside to cool.
Meanwhile, in a medium bowl, whisk together the eggs and season well with salt and pepper.
In a 10-inch oven-safe skillet, add the roasted vegetables, egg mixture and top with the feta cheese.
Sprinkle with parsley and bake for 25-35 minutes, until the frittata has puffed and the center is set. Allow to cool for 10 minutes before slicing into wedges. Serve warm.