Preheat oven to 375°. Fit a 9-inch pie plate with the prepared pie crust. Flute edges. Set aside.
Melt the butter in a skillet over medium high heat. Add in the onion, and cook until just fragrant and tender, about 3 minutes.
Add in the red pepper and garlic and cook an additional 3 minutes, or until the pepper is just tender.
Add the spinach, olives, italian seasoning, and parsley. Cook until the spinach is wilted, about 5 minutes.
Remove from heat and stir in the feta cheese and tomatoes. Spoon the mixture into the prepared pie crust, spreading out
evenly. Set aside.
In a medium-sized mixing bowl, whisk together the eggs, milk, salt, and pepper, and 1/2 cup of the cheddar cheese. Pour this
mixture evenly over the spinach mixture in the pie crust. Sprinkle top with remaining cheddar cheese.
Bake in preheated oven for 50-55 minutes, or until the crust is golden brown and the egg is set. Let cool for 10-15 minutes
before slicing and serving