01 -
Place diced potatoes in a large pot, cover with cold salted water, and bring to a boil. Cook until fork-tender, approximately 15 minutes. Drain thoroughly.
02 -
Mash drained potatoes with butter, milk, salt, and black pepper until creamy and smooth. Set aside.
03 -
Heat a large skillet over medium heat. Add ground beef and cook for 5 to 7 minutes, breaking it apart as it browns. Drain excess fat if needed.
04 -
Add diced onion and minced garlic to the skillet with the beef. Sauté for 3 to 4 minutes until softened.
05 -
Stir in tomato paste, Worcestershire sauce, beef broth, and frozen vegetables. Simmer mixture for 5 minutes until vegetables are tender and flavors have melded.
06 -
Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius).
07 -
Spread the beef and vegetable mixture evenly into a baking dish. Cover with mashed potatoes, smoothing the top.
08 -
Place casserole uncovered in preheated oven and bake for 20 minutes, until topping is slightly golden.
09 -
Allow to cool briefly before serving.