Preheat oven to 350 degrees.
Spray an 8-inch cast iron skillet with olive oil spray. Add the shallots and tomatoes. Cook over medium-low heat for 5 minutes.
Add the eggs, skim milk, salt, pepper, and garlic powder to a medium bowl. Whisk together until blended.
Pour the egg mixture over the tomatoes and shallots. Remove from heat.
Add small dollops of ricotta cheese and sprinkle with Parmesan cheese.
Bake for 35 minutes, or until the eggs are set in the center.