Preheat oven to 400°F.
Brown ground beef, garlic, and onion in a skillet over medium heat until no pink remains. Drain any fat. Stir in diced potatoes and cook 3 minutes more.
Combine barbecue sauce, mustard, ketchup, broth & cornstarch in a small bowl. Pour sauce over the meat mixture. Bring to a boil and let simmer until thickened, about 3 minutes. Pour into a 9-inch round baking dish or pie pan. Top with 1 ½ cups cheddar cheese.
In a medium bowl, combine Bisquick, egg, milk, and ½ cup cheese. Spread over meat mixture and top with sesame seeds.
Bake for 22-27 minutes or until topping is golden and cooked through.
