Preheat your oven to 350°F (175°C).
Heat a large skillet over medium heat and add cooking oil.
Add the ground beef to the skillet and cook until browned, breaking it up into crumbles using a wooden spoon or spatula.
Put the chopped onion and crushed garlic in the skillet and cook them until the onion becomes translucent.
Add the shredded cabbage to the skillet and cook until it wilts, stirring occasionally.
In a separate bowl, combine the condensed cream of mushroom soup, sour cream, dried thyme, salt, and pepper. Mix well.
Pour the soup mixture over the cabbage and ground beef into the skillet. Stir until everything is evenly coated.
Transfer the mixture from the skillet to a greased baking dish.
Over on the top of the casserole sprinkle the grated cheddar cheese.
Preheat oven for 25 minutes, cover the baking dish with foil, and bake.
Continue baking for 10-15 minutes by removing the foil.
Remove the casserole from the oven when cooked, before serving let it cool for a few minutes.