1Grease 8- or 9-inch square baking dish with butter or cooking spray.
2In large bowl, beat eggs, milk and cream cheese until well blended. Stir in mustard, salt, pepper, potatoes, Cheddar cheese, bell pepper and ham. Pour mixture into baking dish. Cover; refrigerate 4 hours or overnight.
3Heat oven to 350°F. Uncover baking dish. Bake 40 minutes. In small bowl, combine topping ingredients. Sprinkle over casserole. Bake 10 to 15 minutes longer or until set and top is golden brown. Cut into 6 squares and cut each square in half diagonally.