Add the olive oil to the tomatoes and place on a cookie sheet to roast for 10 -15 minutes, or until tomatoes burst open and are nicely caramelized.
In the meantime, whisk the eggs in a bowl with a fork. Add the feta, spinach, red pepper, chives and mix well. Season to taste with salt and pepper.
Heat an 8 or 9 inch cast iron pan on your stovetop and place the roasted tomatoes in, then pour the egg mixture on top of the tomatoes and give everything a good stir, don't overcook - the frittata will set in the oven.
Place the pan in the oven for 15-20 minutes. The cooking time will depend on the thickness of your frittata. Simply stick a sharp knife into the middle to test if it has cooked through. Serve warm with a sprinkle of fresh parsley, dill and additional feta cheese.
Recipe by SIMPLY BEAUTIFUL EATING at https://simplybeautifuleating.com/2017/04/05/greek-roasted-tomato-herb-frittata/