Preheat the oven to 375°F. Spray a 9x13 baking dish with oil.
Spray a casserole dish with nonstick spray. In a small bowl combine spinach, scallions, artichoke, red pepper, garlic and dill and any optional meat you’ve chosen. Pour into the casserole dish spreading evenly.
In another bowl, whisk together the eggs, egg whites, milk, parmesan, salt and pepper. Mix in feta cheese and pour over vegetables.
Bake until a knife inserted near the center comes out clean, 32 to 35 minutes. Let stand 8 to 10 minutes before cutting into 8 pieces.