Preheat oven to 350°F. Heat oil in large nonstick skillet on medium-high heat. Add onion; cook and stir 5 minutes or until tender. Remove from skillet. Cool slightly.
Mix milk and flour in large bowl with wire whisk until smooth. Add eggs, egg whites, curry powder, sea salt, garlic powder and ground red pepper; whisk until smooth. Add cooled onion, spinach and ricotta cheese; mix well. Pour into 9-inch deep dish pie plate sprayed with no stick cooking spray. Sprinkle with Parmesan cheese.
Bake 30 to 35 minutes or until top is golden brown and center is set. Let stand 10 minutes before cutting into serving-size pieces.