Start by preheating your oven to 375°F (190°C) to ensure it's hot and ready for baking.
In a large skillet, heat the olive oil over medium heat. Once the oil is shimmering, add the diced onion and minced garlic. Sauté this mixture for about 3-4 minutes, or until the onion becomes fragrant and translucent.
Next, incorporate the ground beef into the skillet. Use a spatula to break the meat into smaller pieces as it cooks. Continue cooking for around 5-7 minutes, or until the beef is browned and no longer pink. Season the mixture generously with salt, pepper, dried oregano, and paprika to enhance the flavors.
Stir in the Worcestershire sauce along with the frozen mixed vegetables. Allow this to cook for another 2-3 minutes, just until the vegetables are heated through. Once done, remove the skillet from heat.
In a greased 9x13 inch casserole dish, arrange half of the sliced potatoes in a single layer at the bottom.
Evenly distribute the cooked ground beef mixture over the layer of potatoes, ensuring it's spread out for consistent layering.
Top the beef layer with the remaining potato slices, creating a second layer of potatoes.
Carefully pour the beef broth over the casserole, taking care that it seeps into the layers for extra moisture and flavor.
Cover the dish tightly with aluminum foil, and place it in the preheated oven. Bake for 30 minutes to allow the flavors to meld and the potatoes to soften.
After 30 minutes, remove the foil and sprinkle shredded cheddar cheese evenly over the top layer of potatoes.
Put the casserole back in the oven, this time uncovered, for an additional 15-20 minutes, or until the cheese is melted and bubbly, and the potatoes are tender when pierced with a fork.
Allow the casserole to cool for a few minutes before serving, as this helps the layers to set.
Notes
Serve hot, optionally garnished with fresh parsley or chives.