Add carrots and water to a large pot; bring to a boil, reduce heat, and simmer until carrots are almost tender, about 15 minutes.
Add the onions, potatoes, rice, macaroni, salt, and pepper and bring to a boil once again; reduce heat and simmer until rice is cooked and vegetables are tender, about 30 minutes more.
(Add more water only if absolutely necessary.
)
Add the milk and butter and stir; heat until hot, but do not boil.
Notes / Tips / Wine Advice:
You can substitute 2 cups heavy cream for the milk and butter if you prefer.