Preheat oven to 350°. Beat together Simply Egg Whites, milk or half-and-half, flavorings and cheese.
Layer spinach, peppers and tomatoes and peppers in a buttered deep dish glass pie plate, arranging top layer attractively. Carefully pour egg mixture over layers.
Bake 40 to 45 minutes until a knife inserted in center comes out clean. Let sit 15 minutes before cutting.