Preheat oven to 350°F.
Brown ground beef over medium heat in large skillet. Break up all lumps until it is evenly crumbled.
Drain grease from meat and remove from skillet. Set aside to cool.
Sweat onions (until translucent) in same skillet (do not clean) and add garlic.
Pour ground beef back into skillet over onions and garlic.
Add gravy, carrot, salt, and pepper.
Raise heat and bring to a simmer for about 15 minutes or until carrot is tender.
Pour mixture into 9" deep baking dish and top with prepared mashed potatoes.
Bake for approximately 45 minutes.