Using a 12 inch cast iron skillet, fry the bacon, drain, set aside.Remove any excess bacon grease, leaving just enough to coat the pan. Add cubed potatoes, and spread out in pan. Salt and pepper them, and allow to brown. After about 5 minutes or so, turn potatoes over, and season again. Cover the pan with a lid, to allow potatoes to steam to cook through. This may take another 5010 minutes. Test potatoes for doneness when fork goes through easily.
While potatoes are frying, whisk eggs, sour cream, & pepper in a large glass bowl with a pour spout. Set aside.
When potatoes are done, add in the egg mixture.
Let cook for 1 minute, do not stir
Sprinkle cheddar cheese over egg mixture
Sprinkle bacon in next
Add spinach, pushing down into egg mixture
Sprinkle gouda cheese over spinach
Arrange the tomatoes on top, cut side down
Season with several grinds of black pepper
Bake for 25 minutes, turning half way thru
When golden brown, and eggs are slightly firm remove from oven
Allow to sit for at least 5 minutes
Can be served warm, and delicious cold next day in lunch!
Notes
A well seasoned cast iron is the best pan to use for a frittata.