Preheat oven to 400℉. Coat a 9-inch quiche pan or deep-dish pie plate with cooking spray and set aside.
In a large skillet, melt 1 tablespoon butter over medium heat. Add potatoes and sauté until tender. Sprinkle with salt to taste.
Transfer potatoes to prepared pan.
In the same skillet, melt the remaining 1 tablespoon butter and soft scramble the eggs, leaving them fairly liquid. Salt and pepper to taste.
Spread half of the cheddar and Swiss cheese in a thin layer over potatoes. Spread sour cream over cheese, and sprinkle with chives. Add eggs, and top with remaining cheddar and Swiss cheese.
Circle quiche pan with tomato slices and sprinkle with Parmesan cheese.
Bake approximately 35 minutes until cheese is completely puffy and slightly browned.
Slice and serve.