Peel potatoes and cut into 1-inch chunks. Put the potatoes into a large pot and cover with cold water. Bring to a boil over medium-high heat, reduce heat and cook until the potatoes are tender, about 15-20 minutes.
Meanwhile, steam cauliflower until very tender.
Drain potatoes and combine with cauliflower. Add milk and mash with a potato masher. Add salt, pepper and nutmeg.
Garnish with shredded carrots and chopped fresh parsley.