Combine spinach, hash brown potatoes, carrot, red pepper, green onion and basil in large bowl. Stir in eggs, mayonnaise and sour cream. Season with salt and pepper. Spray a 9 inch (23 cm) square baking pan with cooking spray. Spread egg mixture in pan. Bake in preheated 350 F (180oC) oven until knife inserted in centre comes out clean, about 35 to 40 minutes.
Serve warm or cold, as a breakfast frittata, a meatless main dish or a vegetable side dish. Leftovers can be reheated in the microwave.