In a large pot, cook potatoes and garlic for 20-25 minutes, or until potatoes are tender and ready to mash.
Meanwhile, heat oven to 375 degrees Fahrenheit. Brown ground beef in a large saucepan. Stir in flour and cook for one to two minutes. Add ketchup, beef broth and frozen vegetables and cook for 5 minutes, stirring frequently.
Drain the potatoes. Add sour cream, and mash potatoes until they’re smooth and creamy.
Spoon meat and vegetable mixture into an eight-inch square baking dish. Sprinkle with salt and pepper. Cover meat with a thick layer of mashed potatoes.
Bake for 20 minutes. (If desired, top pie with shredded sharp cheddar cheese and cook for an additional two minutes, or until cheese is melted).