Two-Tone Mashed Potatoes

1 pound (about 6) potatoes
1 pound (2-3 large) sweet potatoes (the lighter colored ones have a nice mild flavor, but the more orange ones look pretty next to the white potatoes)
4 tablespoons milk
4 tablespoons butter
1 tub onion and chive flavor cream cheese
1/4 cup parmesan cheese
salt and pepper to taste

Wash, peel, and boil the potatoes and sweet potatoes until tender. Mash the potatoes with half of the milk, butter, and cream cheese. Spread in a 9x13 dish and sprinkle with half of the parmesan cheese. Do the same with the sweet potatoes, spreading over the potatoes. Bake at 350 for 15 minutes, or until warmed through.