Preheat oven to 400°F. Peel and chop the potatoes, then boil in salted water until tender.

Meanwhile, in a large skillet, heat olive oil over medium heat. Add diced onion and minced garlic, sauté until translucent.

Add ground beef to the skillet, cook until browned. Pour in beef broth, add salt and pepper, and simmer until the mixture thickens slightly.

Drain cooked potatoes and mash with milk and butter until smooth. Season with salt and pepper.

Transfer the beef mixture to a baking dish, spread mashed potatoes evenly over the top.

Bake in the preheated oven for 25-30 minutes until golden brown on top.