01 -
Preheat your oven to 190°C (375°F). Lightly grease a 9x13-inch (approx. 23x33 cm) baking dish.
02 -
In a large skillet over medium heat, cook the ground beef and diced onion until the beef is thoroughly browned and no longer pink, approximately 6–8 minutes. Carefully drain any excess fat from the skillet.
03 -
Add the minced garlic and sliced mushrooms to the skillet with the beef and onion. Continue to cook for an additional 5–6 minutes until the mushrooms have softened and become fragrant.
04 -
Stir in the cream of mushroom soup, sour cream, paprika, dried thyme (if using), salt, and pepper into the skillet mixture. Mix thoroughly until all ingredients are evenly combined and the sauce is smooth.
05 -
Transfer the entire beef and mushroom mixture into the prepared baking dish, spreading it out evenly. Generously sprinkle the shredded cheese over the top surface.
06 -
Bake the casserole, uncovered, for 25–30 minutes, or until the cheese is beautifully melted, golden, and the casserole is bubbling hot throughout.
07 -
Allow the baked casserole to rest for a few minutes before serving. Enjoy it on its own or serve over cooked egg noodles, rice, or cauliflower rice for a complete meal.