Peel and chop the potatoes into chunks, boil in salted water for 7-8 minutes until fork-tender, then mash with butter, milk, garlic powder, salt, and pepper.

Cook ground beef in a skillet over medium heat until browned, break apart with a spoon, then drain excess fat.

Add chopped onion to the skillet and sauté for 5 minutes, then add beef broth and seasonings; simmer for 5-10 minutes.

Mix cornstarch with broth to create a slurry, add to skillet, stir, and bring to a boil to thicken the gravy.

Serve mashed potatoes topped with the beef and gravy.