Cover potatoes & garlic with water in a large saucepan. Bring to a boil. Reduce heat simmer for 20 min. Drain. Return to the saucepan with sour cream. Mash. Stir in ¼ c cheese.
Brown hamburger. Stir in flour. Add veggies, broth & ketchup. Cook for 5 min.
Spoon meat mixture over mashed potatoes. Top with remaining cheese.