Preheat oven to 375°F (190°C). Grease a baking dish with olive oil.
In a skillet over medium heat, sauté diced onion and garlic until fragrant.
Add ground beef to the skillet and cook until browned. Drain excess fat.
Stir in salt, pepper, paprika, and dried thyme.
In a mixing bowl, combine cream of mushroom soup and milk.
Layer half of the sliced potatoes in the greased baking dish.
Spread half of the cooked beef mixture over the potatoes.
Pour half of the soup mixture over the beef.
Repeat the layers and top with shredded cheddar cheese.
Cover with foil and bake for 45 minutes.
Remove foil and bake for another 15 minutes until cheese is golden and bubbly.
Let it cool for a few minutes before serving. Garnish with chopped parsley.