Heat oven to 375°F. Bake potatoes about 1 hour or until tender.
Cut each potato in half crosswise; scoop out inside into large bowl, leaving a thin shell. Mash potatoes until no lumps remain. Stir in cheeses, 1/4 cup parsley, the pepper and egg until well blended.
Increase oven temperature to 400°F. Cut thin slice from bottom of each potato half if needed to stand upright. Place shells on ungreased 15x10-inch pan with sides; fill shells with potato mixture.
Bake about 20 minutes or until hot. Garnish with additional parsley and bell pepper.