Heat the oven to 350 degrees and grease an 8x9" baking dish.
Whisk together the water, soup, and milk.
Add the mushroom mix, rice, cooked beef and carrots to a bowl and stir to combine.
Dump into an 8x9" baking dish and bake, uncovered for 90 minutes. Add cheese on top and return to the oven for another couple of minutes or until the cheese is melted.
* I added a dash of garlic salt, pepper, and a little cheese in mixture before baking.