Preheat oven to 450°.
Line unpricked pastry shell with heavy duty aluminum foil. Bake at 450° for 7 minutes. Remove from the oven and remove foil; set aside.
Reduce heat to 300°.
In a large skillet, cook sausage until no longer pink; drain well in colander.
Place cottage cheese, cream cheese and egg in blender; cover and process until smooth.
Transfer to large bowl;stir in potatoes, sour cream, oregano, garlic powder, salt and pepper.
Place sausage in pastry shell; top with potato mixture. Drizzle with butter.
Bake for 50-60 minutes until light golden brown and a little crisp on top.
Sprinkle with cheeses and let stand until melted.
Garnish with tomatoes tossed with minced parsley if desired.