Sauté mushrooms in 1/2 tsp olive oil - set aside to cool.
Sauté spinach & chopped garlic in 1 tsp olive oil, spinach will wilt, cool.
Whisk eggs in bowl & fold in mushrooms & spinach, add sun-dried tomatoes, salt & pepper. Pour egg mixture into oiled (1/2 tsp) cast iron skillet, sprinkle parmesan & spoon ricotta on top, cooking on medium until firm.
Transfer cast iron skillet into broiler & heat for another 10 minutes; eggs will rise slightly.