1. Place the peeled, cubed potatoes in a pot, cover with water, and boil until fork-tender, about 15–18 minutes. Drain well.

2. Mash the potatoes with butter, milk, salt, and pepper until smooth. Stir in cheddar cheese if using. Set aside.

3. In a large skillet, heat olive oil over medium. Sauté diced onion for 3–4 minutes, then add garlic for 30 seconds.

4. Add ground beef and cook until browned, about 6–8 minutes. Drain excess fat.

5. Stir in tomato paste, Worcestershire sauce, thyme, salt, and pepper. Sprinkle with flour and mix well.

6. Pour in beef broth and bring to a simmer. Add frozen vegetables and cook until mixture thickens, about 5–6 minutes. Remove from heat.

7. Preheat oven to 400°F (200°C). Spread the meat mixture evenly in a 9×13-inch baking dish.

8. Spoon mashed potatoes over the top, smooth or create ridges with a fork.

9. Bake uncovered for 20–25 minutes, or until golden and bubbling. Broil for 2–3 minutes for a crispy top, if desired.

10. Let rest for 10 minutes before serving. Garnish with parsley.