Place cut potatoes in a large saucepan or dutch oven, cover with cold water and stir in 2 teaspoons salt and bring to a boil over high heat.
Once the water come to a boil reduce heat to medium high to maintain the boil and cook for about 10 minutes more or until potatoes are fork tender.
Take the pot away from heat and carefully drain all the water, mash with a potato masher to your desired consistency.
Preheat oven to 350F and spray a 3 quart baking dish.
Place milk and butter in a microwave safe measuring cup or bowl and heat just until butter melts.
Cut cream cheese into small cubes and add to the pot.
Stir in half the cheddar and half the mozzarella cheese.
Pour in hot milk and mix everything well with a wooden spoon.
Season with salt and black pepper.
Spread potatoes on your baking dish and sprinkle the remaining cheese on top.
Cover and bake for 15 minutes then uncover and bake for another 5 minutes or until cheese melts and browns a bit to your liking.
Garnish with chopped fresh parsley or chives and serve.